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Hello this is Martez or Curdy and it is really really going to actually make is it equal Potten work.



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So just open your a calculator calculator job fine.



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And here we have the uncle of it.



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So if you go inside is switch statement.



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We have this case are that ID that PTEN equal.



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So now inside this case we are going to call.



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Operator is tapped method.



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And we're going to pass the the equal operator as the argument to this method.



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So operator that you call.



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So now that's enough.



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OK.



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Just calling this if it is enough in order to make a disobedient equal work because then this method



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is called here the operator is tapped is called and are actually passing the equal operator to this



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method.



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First as you can see the current operator is not equal to not because the equal operator is actually



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passed because or some operation has actually been executed.



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So the current operator is not not.



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And if it is not then it's not going to actually secure this if statement is it's going to actually



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be assigned a current number to this street number at.



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Right.



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And then it's going to actually set the empty value to this current number variable.



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And this switch statement is going to be executed.



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So now let me show you the emulator here.



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For example we have number five.



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OK.



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Number five multiplied by two.



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OK.



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And now I'm going to press on this equal button.



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The result is going to be output to the console.



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So here when I say this switch statement is going to be executed.



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So first you can see that the current number is going to be assigned to this strange number.



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That's right.



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So here we have the number 10.



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OK.



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But now when the switch statement is going to be executed it is switching between the values of the



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current operator.



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When I say the current operator is that it doesn't mean that the current operator is actually equal



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operator because at the end of this operator is that method we are going to update the value of this



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current operator variable.



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So at the end of the Smurfette here you can see in line number of 199 you are assigning the tapped operator



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to the current operator.



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So for example when I say 5 multiplied multiplied by two.



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OK.



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Now if I press on is equal button here it doesn't mean that now the current is equal but equal operator



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is the current operator.



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Is that just a tapped operator.



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The current operator is that multiplication operator that I pressed before this equal operator.



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So now here let's actually circle with.



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Here it says.



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So each count operator.



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So it's going to switch between the values of the current operator in our case we said that.



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So let me just explain again.



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We said to multiply it by five.



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In anti-state current operator is multiplication operator right.



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So here it's going to actually take a look at this case statement case multiply and it's going on just



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calculates the result at street number left multiplied by a string number that's right.



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And the result is going to be assigned to these calculations the result variable.



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Right.



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And then it's going to go down here after this.



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Any curly brace is going to update the value of this string number that's left by actually assigning



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the calculation result to this variable.



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And then the value is going to be displayed on the screen.



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So test results that said text string number at left.



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And finally we are actually updating the value of these calculations strange in order in order to show



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this value to the user at the top here.



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So now we can actually run the app and here you can see that after executing these lines of code here



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this statement here is not going to be executed because the current operator is not equal to null.



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If an operation is actually occurring and then the task of Rotary is going to be the current OPERATOR



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OK.



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So now we can actually run the app.



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We can't say run and let me show you the emulator.



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So for example if you have number five multiply by two here now I'm going to press on this this one



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this call button.



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Now the result is and with it here to the screen.



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OK.



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So now you can't I told you that the current operator is going to be the tapped OPERATOR Right.



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OK.



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So now I'm going to say number 10.



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He had to resolve it multiplied by two equal operator and now our application is crashed.



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So this means that there is a bug inside our application.



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First of all it's in order to find the bug we need to take a look at the locks.



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The first step is to take a look at the locks.



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So at that point I'm going to click on this Lochhead here.



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So let me show you the locks.



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And here it says.



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Let me actually show you here.



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So now here we're going to take a look at the right texts.



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Actually the it takes are going to show you are the exact park the fatal exception.



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And here it says that there is a number format the exception for input screen empty screen.



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Here you can see that here.



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And we've got two links actually the first one is calculator file Java line.



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If you click on it it's going to actually highlight the operator is tapped method calling him for the



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speedy and equal case and the next one is actually the triangulated job.



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One hundred and sixty.



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The air is accurate here.



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And you can see that this three numbers at lift.



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Valuable is highlighted so there is something right here inside the arch of light.



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So let me close at this last check here in order to find the bag.



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We don't have to look through the codes in order to find the bag and kill it so that our application



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works.



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That's not how it is designed.



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That's not how it works.



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We've got debugging tools at our hands that we can use it in order to find the bug and solve it.



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So how we can actually use these debugging tools.



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So first of all we know that US there is something wrong with our sync number lift method or variable



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actually.



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So I'm going to create a debugging point of red point here for this operator is Taft's of Meffert.



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So in line number of 148 here when I actually create this method uprated is that I'm going to create



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our red point for this effect.



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It is called a debugging point so that we can actually debug from this line of code.



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And then we can actually step by step by step see what's wrong with our coats.



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So now I'm going out run the app I'm going to.



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So I'm not going to run the app.



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We've got another option.



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We've got debug the app.



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You can see this one here a bug a great bug and you can see this play about it here on this great park.



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So just click on this one unless he has an emulator and then click on it.



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Let me show you the emulator.



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So it's it's as is waiting for people here.



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So let's wait now it is ready.



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Now I have number five.



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OK.



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So I'm going to just click on number five multiplied.



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So now the debulking is started.



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So if you're going to step by step see what's wrong with our code and see exactly how to debug the app



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now.



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Team effort OPERATOR This is actually called because I clicked on this multiplication operator.



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So that's why the debugging is now started because I created this red point for this method.



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Operator Is that here we have some options some icons.



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The first one says step over step over is going to execute the current code.



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The current line of code in its entirety.



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So we're going to execute that line of code in its entirety so that we can step over as you can see



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it wanted to actually execute this line of code.



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If current operator is not equal to no.



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So the current operator is actually not all because of an I pressed on this multiplication operator



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are the current operator is null.



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We have a tapped OPERATOR So you can see that it's as the tag the operator is multiply.



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But the current operator is not.



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So this if statement here is not going to be executed.



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So the flow of the program is going to go in so it is else that it isn't right and it's going to execute



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this line of code.



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It says string number at lift.



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Assignment operator current number.



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So we've got the current number which is number five.



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And here you can see that here.



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So it has a number that is not.



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And you've got a kind of number which is number five.



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So the number five is going to be assigned to the string number at left.



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If I could kind of step over now this line of code is going to be executed and the number 5 is going



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to be assigned to this number Atlas.



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So let me click on it.



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Now it's going to say that there's three numbers is number five.



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And here we want to assign an empty string value to this column number valuable.



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So it says that the current value of the current number value is 5 but then it this line of code here



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is going to be executed of this line of code is executed the empty value the empty string value is going



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to be assigned to this kind of number right.



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So let me click on this over.



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Now are we just see if they actually hover over this number here we can see that an empty string value



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is a science that is valuable.



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00:10:24,900 --> 00:10:30,310

Now I was going to ask you this line of code the tap's operator is going to be assigned to the current.



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OPERATOR OK.



162

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So now the card operator is going to be the multiplication operator.



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So if I show you the emulator and now if I click on this step over.



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Now it says the current operator is multiply the top rated is also multiplied right.



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So now is it reached to the end of this method.



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Now if I click on that over again.



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Now you can see that this line of cohered is executed the operator is tapped and you can see that it's



168

00:11:03,050 --> 00:11:06,020

going to assign this value to this variable calculation string.



169

00:11:06,020 --> 00:11:11,660

So there is not there is nothing wrong with our calculations or the calculations.



170

00:11:11,900 --> 00:11:15,350

So if going to just resume the program.



171

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So at the left hand side you can see these left sidebar of this debulking area.



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It is a resume program.



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So let's click on resume program.



174

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So it might be five multiplied by for example 6.



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Now I'm going to click on this equal.



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Operator.



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So again the operator is tapped.



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Method is called.



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OK.



180

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So that it's going to again take a look at this if statement if current operator is not equal to not.



181

00:11:44,770 --> 00:11:49,590

So the current operator is not equal to now because the current operator is the multiplication operator



182

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and the current number is not equal to an empty stream.



183

00:11:54,520 --> 00:11:56,280

Value.



184

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So it says true the current number is not equal to actually an empty string value.



185

00:12:04,430 --> 00:12:10,100

So it is true you can see that this value here because we press undersexed number sets.



186

00:12:10,130 --> 00:12:17,810

So if I click on step over this if statement evaluates to true and is going to execute this if statement



187

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is going to actually is the this line of code.



188

00:12:19,970 --> 00:12:22,960

So the cost number is going to be assigned to district number.



189

00:12:22,970 --> 00:12:23,490

That's right.



190

00:12:23,510 --> 00:12:24,920

The current Nobody is number six.



191

00:12:24,920 --> 00:12:32,570

So if I can step over we can see that it is screen number X-Rite is sex and about the current value



192

00:12:32,570 --> 00:12:34,250

of the current number is 6.



193

00:12:34,250 --> 00:12:37,930

Now we want to assign an interesting value to the kind of number.



194

00:12:38,150 --> 00:12:42,790

So if I click on that over now it is the kind of number value is empty string.



195

00:12:43,070 --> 00:12:45,000

So now going to execute the switch statement.



196

00:12:45,020 --> 00:12:47,570

Let's get this step over.



197

00:12:47,780 --> 00:12:53,790

So we know that the counter-protest is multiply so it's going to execute this case multiply.



198

00:12:54,300 --> 00:13:00,420

And here we are going to actually you can see that it says our calculation result is zero the value



199

00:13:00,420 --> 00:13:04,670

of this variable is zero and the string length is 5.



200

00:13:04,670 --> 00:13:07,820

So let me kind of step over now.



201

00:13:07,850 --> 00:13:11,400

It says now that we have five I think number three is six.



202

00:13:11,450 --> 00:13:13,990

OK because we press on number 6.



203

00:13:14,210 --> 00:13:20,940

So if I can step over now the calculations result is going to be the value of the calculation.



204

00:13:20,950 --> 00:13:22,980

The result is going to be 50.



205

00:13:23,270 --> 00:13:29,180

So let me show you that here's the number if these five calculation result is 50 so you want to assign



206

00:13:29,510 --> 00:13:33,980

the value of the calculation results to the string number at left here.



207

00:13:34,010 --> 00:13:42,350

So if you click on this step over this line of code is executed it says change relations result 40 and



208

00:13:43,250 --> 00:13:44,720

it's going to secure this value.



209

00:13:44,840 --> 00:13:50,710

So it's going to output the value of the string number at left of the screen.



210

00:13:50,790 --> 00:13:53,670

And finally it's going to be the cutest line I've got here.



211

00:13:53,880 --> 00:14:01,800

So and finally here after these these lines of code is going to assign the tapped operator to the current



212

00:14:01,800 --> 00:14:08,070

operator so that half the operator is actually equal we can see that here the equal of right is going



213

00:14:08,070 --> 00:14:11,050

to be assigned to this current operator.



214

00:14:11,070 --> 00:14:13,080

So effectively conc that over again.



215

00:14:13,080 --> 00:14:16,700

Now this line of code is executed the current operator is equal.



216

00:14:16,950 --> 00:14:23,460

And now I'm going to click on the over again so you can see that this line of code here is actually



217

00:14:23,460 --> 00:14:26,830

going to be executed equal.



218

00:14:26,910 --> 00:14:32,210

And here because the operator restaffed and we said operator that equal and beep at Preston the equal



219

00:14:33,330 --> 00:14:34,200

button.



220

00:14:34,230 --> 00:14:38,320

So we're going to click on this over again.



221

00:14:38,790 --> 00:14:40,450

And finally it's going to secure the line of code.



222

00:14:40,450 --> 00:14:46,920

So there is nothing wrong with our takes the triangulation So if you're going to just resume the program



223

00:14:46,920 --> 00:14:52,050

resume program by just clicking on the play button here inside this debugging area.



224

00:14:52,050 --> 00:14:55,400

So not the number 50 here is out with it with this screen.



225

00:14:55,590 --> 00:14:56,400

OK.



226

00:14:57,240 --> 00:15:01,070

So now we have number 50 as the result.



227

00:15:01,080 --> 00:15:05,770

Now I'm going to say 40 plus.



228

00:15:05,880 --> 00:15:08,700

So here this is really important here.



229

00:15:08,910 --> 00:15:15,780

It is where we actually find the park and just notice that here I am actually teaching you advanced



230

00:15:16,350 --> 00:15:23,700

debugging in Android so make sure to pay attention to what I'm teaching you because this is very important



231

00:15:23,700 --> 00:15:27,370

and it's going to help you a lot in your future Android projects.



232

00:15:27,570 --> 00:15:32,520

If you are Android If you're actually an Android Developer and don't know how to debug an app you're



233

00:15:32,550 --> 00:15:34,930

going to encounter lots of problems.



234

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Trust me.



235

00:15:36,120 --> 00:15:39,650

So now just up here tension here.



236

00:15:39,900 --> 00:15:43,700

I actually press on the plus operator here.



237

00:15:43,710 --> 00:15:44,340

Right.



238

00:15:44,670 --> 00:15:50,820

So now at the affrightedly Statham if it is called Here we say if the current operator is not equal



239

00:15:50,820 --> 00:15:53,060

to and also the current operator is equal.



240

00:15:53,240 --> 00:15:53,820

OK.



241

00:15:54,000 --> 00:15:56,700

Here you can see the value of the current operator.



242

00:15:56,700 --> 00:15:58,110

So it is not equal to all.



243

00:15:58,140 --> 00:16:06,020

And here it says and the current number is not equal to an empty stream given you.



244

00:16:06,030 --> 00:16:10,810

So it's is true the kind of number is not equal to an empty string value.



245

00:16:10,920 --> 00:16:11,810

Right.



246

00:16:12,370 --> 00:16:23,580

And here I'm going to actually just click on step over so there is something wrong here OK.



247

00:16:23,750 --> 00:16:25,170

There is something wrong here.



248

00:16:26,060 --> 00:16:30,830

The current number is actually no it's not not.



249

00:16:30,860 --> 00:16:36,780

It is actually the value of the kind of number it is an empty string value.



250

00:16:36,780 --> 00:16:41,770

You can see that here canit number is not equal to an empty string value and it is true.



251

00:16:41,790 --> 00:16:46,460

This means the current number is actually empty.



252

00:16:47,210 --> 00:16:54,440

And that's why this statement here didn't execute and it the flow of the program went into the else



253

00:16:54,440 --> 00:16:55,600

statement here.



254

00:16:56,880 --> 00:16:57,590

OK.



255

00:16:58,020 --> 00:16:58,980

So when I pressed on.



256

00:16:58,980 --> 00:17:03,150

So we have the result 30 and I pressed on the plus operator.



257

00:17:03,330 --> 00:17:08,750

Now it wants to execute the SQL statement.



258

00:17:08,800 --> 00:17:14,830

So now if it wants to assign the current number which is actually an interesting value to this three



259

00:17:14,830 --> 00:17:16,450

number I left.



260

00:17:16,450 --> 00:17:21,780

So here you can see that it says that the value of the current number is empty.



261

00:17:21,850 --> 00:17:24,780

It's just showing us the value of the current number.



262

00:17:24,880 --> 00:17:27,950

So this empty value is going to be assigned to the string number.



263

00:17:28,120 --> 00:17:29,950

Let's click on step over.



264

00:17:29,950 --> 00:17:36,310

Now you can see that the value of this thing number at live is actually an empty string value and the



265

00:17:36,310 --> 00:17:41,460

value of the current number is also an empty string value.



266

00:17:41,650 --> 00:17:42,270

Right.



267

00:17:43,440 --> 00:17:47,990

If I actually kind of step over again now the tapped operator is going to be assigned to the current



268

00:17:47,990 --> 00:17:48,760

operator.



269

00:17:48,950 --> 00:17:52,660

So the current operator is going to be Plus the plus operator.



270

00:17:52,700 --> 00:17:58,670

So if I actually kind of step over is going to go on I can see that it's this case a statement between



271

00:17:58,670 --> 00:17:59,980

the plus is executed.



272

00:18:00,200 --> 00:18:05,680

So there is nothing wrong with this line of code so we're going to just resume the program.



273

00:18:06,020 --> 00:18:17,560

So we have 40 plus and not is that now the value of the string number at lift is an empty string value.



274

00:18:17,780 --> 00:18:29,730

And that's where the bug is so if I can for example number five and if I click on these equal operator



275

00:18:30,090 --> 00:18:33,670

here here the app is going to crash.



276

00:18:33,760 --> 00:18:40,240

But because we created a debugging point here a red point we can actually control the flow of the program.



277

00:18:40,240 --> 00:18:44,530

So now I'm going to show you that the app is actually going to crash.



278

00:18:44,840 --> 00:18:52,120

Now you know that we have that kind of operator is plus and the current number is five because I pressed



279

00:18:52,120 --> 00:18:53,350

on the number five here.



280

00:18:53,580 --> 00:18:54,000

OK.



281

00:18:54,070 --> 00:18:55,820

So I'm going to ask you this if statement.



282

00:18:56,110 --> 00:19:00,820

If I click on this here so let me show you that if I actually show you that.



283

00:19:00,850 --> 00:19:01,770

Let's click on this.



284

00:19:01,780 --> 00:19:03,270

Step over.



285

00:19:03,280 --> 00:19:08,140

Now the value of the current number if it is actually number five is going to be assigned to the string



286

00:19:08,140 --> 00:19:08,550

number.



287

00:19:08,580 --> 00:19:15,560

And right so we have number five as the value of the string number.



288

00:19:15,790 --> 00:19:16,700

That's right.



289

00:19:16,960 --> 00:19:23,650

And we're going to execute this kind of number this line of code and an empty string value is going



290

00:19:23,650 --> 00:19:25,670

to be assigned for the current number.



291

00:19:25,990 --> 00:19:27,880

So let's kind of step over.



292

00:19:27,920 --> 00:19:33,520

And now he's going to is a huge statement and the current operator is Plus if I click on this that over



293

00:19:33,520 --> 00:19:33,820

again.



294

00:19:33,820 --> 00:19:40,060

So this case statement here is going to be executed case plus calculations with the assignment operator



295

00:19:40,090 --> 00:19:43,310

integers that parse and string number.



296

00:19:43,350 --> 00:19:45,870

Absolutely if it's.



297

00:19:46,000 --> 00:19:52,240

So if I hover over this string number at length it means it says that the value the current value of



298

00:19:52,240 --> 00:19:56,560

this string number at left is an empty string value.



299

00:19:56,650 --> 00:20:02,020

So we cannot convert an empty string value to an integer value.



300

00:20:02,050 --> 00:20:12,330

So what happens when I click on this tip over our app crashed and if I click on a resume here you can



301

00:20:12,330 --> 00:20:14,850

see that the application crashed.



302

00:20:14,850 --> 00:20:19,210

So we found the park and now we need to solve that part.



303

00:20:19,500 --> 00:20:27,400

So let me close this for let's little into this calculator that will file and here the problem is inside



304

00:20:27,400 --> 00:20:34,690

this line of code this approach to restaffed method we need to create an initial statement for the kind



305

00:20:34,690 --> 00:20:39,360

of number is not equal to gnarl is not equal to empty string value.



306

00:20:39,400 --> 00:20:49,450

So by using an and logical operator at a park actually went inside our application.



307

00:20:49,800 --> 00:20:55,410

So here we need to use an if statement instead of an and and logical operator.



308

00:20:55,620 --> 00:20:56,370

Right.



309

00:20:56,700 --> 00:21:07,550

So here we can go inside each statement and see if current number is not equal to an empty string value.



310

00:21:08,400 --> 00:21:12,930

Then we can open and close this statement by using these curly braces and we can actually delete this



311

00:21:12,930 --> 00:21:15,810

part of this if statement here.



312

00:21:16,080 --> 00:21:18,900

And we don't want to use this as a logical operator.



313

00:21:19,080 --> 00:21:25,320

So here we use an inner ears and in a if statement instead of an ontological operator.



314

00:21:25,350 --> 00:21:30,510

So if we're going to actually delete does anything really break out of this if Karez number is not equal



315

00:21:30,510 --> 00:21:32,660

to interesting value.



316

00:21:33,150 --> 00:21:43,550

And if you're going to put the 88 in curly brace here before dispells a statement here OK.



317

00:21:44,040 --> 00:21:53,850

So now this you can see that now dispells statement here is only related to this current number if current



318

00:21:53,850 --> 00:21:55,540

operator is not equal to.



319

00:21:55,540 --> 00:22:03,390

Now if statement not the inner one does one if the current number is not equal to an empty string value



320

00:22:03,870 --> 00:22:04,660

OK.



321

00:22:04,800 --> 00:22:10,610

So whenever this statement here is kind of operator is not equal to null.



322

00:22:10,640 --> 00:22:17,790

If whenever this condition fails then the else statement here is going to be executed.



323

00:22:18,000 --> 00:22:18,470

OK.



324

00:22:18,570 --> 00:22:25,080

And if this condition here is kind of the number is not equal to an empty string value here if this



325

00:22:25,080 --> 00:22:31,350

condition fails it's not going to execute the else statement because inside the else statement we are



326

00:22:31,350 --> 00:22:36,500

actually assigning an empty string value to the current number.



327

00:22:36,890 --> 00:22:41,590

OK so that's the cause of the error.



328

00:22:41,610 --> 00:22:46,670

So now let me actually delete this a breaking point.



329

00:22:47,980 --> 00:22:48,970

By just clicking on it.



330

00:22:48,970 --> 00:22:57,260

And now if you run the app let me show you the emulator.



331

00:22:57,300 --> 00:23:06,260

So for example we have number five multiplied by free equal to 15 plus free.



332

00:23:06,280 --> 00:23:10,830

Now if I click on is equal here our application is not going to crash.



333

00:23:10,840 --> 00:23:14,260

The result is going to be shown to the user number 18.



334

00:23:14,260 --> 00:23:16,120

Now the error is solved.



335

00:23:16,480 --> 00:23:17,040

OK.



336

00:23:17,050 --> 00:23:17,900

If you want to.



337

00:23:17,980 --> 00:23:23,370

So we can actually also create a breaking point here again for this operator is that.



338

00:23:23,370 --> 00:23:30,650

So let's again click on this debugging here debulking and let me show you the emulator because I want



339

00:23:30,650 --> 00:23:37,250

to show you now the bug is killed and we can actually run the app smoothly and see for example Number



340

00:23:37,280 --> 00:23:41,660

five plus number five plus.



341

00:23:42,070 --> 00:23:47,640

So he had his papped operator is plus and the current operator is null.



342

00:23:47,740 --> 00:23:54,850

So this means that this if this condition here it evaluates to false this condition here fails.



343

00:23:54,850 --> 00:23:56,800

And now it's going to execute the else statement.



344

00:23:56,800 --> 00:23:58,550

If I click on this that over.



345

00:23:58,750 --> 00:24:02,960

So you can see that the card somebody is going to be assigned to district number at left.



346

00:24:03,310 --> 00:24:08,260

And here the current number the value of the currency nobody is going to be emptied.



347

00:24:08,300 --> 00:24:09,370

Right.



348

00:24:09,380 --> 00:24:14,420

So now it's going to assign the taps operator to the current operator.



349

00:24:14,420 --> 00:24:17,350

The operator is Plus So if it is secure the sign of code.



350

00:24:17,420 --> 00:24:19,790

Now the current operator is going to be plus.



351

00:24:19,790 --> 00:24:27,600

So let me resume the app so five plus two equal.



352

00:24:27,820 --> 00:24:33,040

So again the affrightedly Statham's if it is called So now it's going to again execute this brief statement.



353

00:24:33,040 --> 00:24:39,610

So if current operator is not equal to not so now the current operator is the plus OPERATOR OK.



354

00:24:39,790 --> 00:24:42,120

If I click on this it's over.



355

00:24:42,190 --> 00:24:46,430

Now this condition evaluates to true and the current operator is not equal to.



356

00:24:46,450 --> 00:24:52,560

So we have this condition if current number is not equal to an empty string value.



357

00:24:52,560 --> 00:24:57,510

The number is not equal to an empty string value because I pressed on this number two.



358

00:24:57,730 --> 00:25:02,550

So again if I had this condition here evaluates to true and it's not a fake.



359

00:25:02,650 --> 00:25:05,680

So if I click on this is that over.



360

00:25:05,800 --> 00:25:11,360

Now it's going to take you design I've got Charon's number is going to be assigned to this thing number



361

00:25:11,580 --> 00:25:12,250

three right.



362

00:25:12,260 --> 00:25:13,220

Valuable.



363

00:25:13,240 --> 00:25:18,880

So it's this number right 30 is now null the value of this value business is now null but the value



364

00:25:18,880 --> 00:25:20,310

of the current number is two.



365

00:25:20,500 --> 00:25:24,740

So number two is going to be assigned to district number and right variable.



366

00:25:24,820 --> 00:25:30,970

If I step over here you can see the value of this string number that's right to and an empty string



367

00:25:30,970 --> 00:25:33,640

value is going to be assigned to this current number.



368

00:25:33,640 --> 00:25:39,910

So if I click on this step over here now is going to execute the switch statement.



369

00:25:39,910 --> 00:25:45,720

So I pressed on the plus OPERATOR Right the current operator is now a plus.



370

00:25:45,730 --> 00:25:52,780

So if I click on step over so it's going to secure this case plus and it's going to just add the value



371

00:25:52,780 --> 00:25:54,590

of the string number at left.



372

00:25:54,760 --> 00:26:00,100

So you can see the value of this number at a fixed number of Y to the value of the street number and



373

00:26:00,250 --> 00:26:02,380

right which is number two.



374

00:26:02,620 --> 00:26:08,440

So the result is going to be assigned to the calculation result and it's going to actually execute this



375

00:26:08,440 --> 00:26:09,580

line of code here.



376

00:26:09,760 --> 00:26:14,740

So number ASLEF assignment operators think that the value of calculation is result the value of the



377

00:26:14,740 --> 00:26:16,170

calculation result is numbers.



378

00:26:16,180 --> 00:26:23,240

And so number seven is going to be assigned to the string number and left and execute this line of code.



379

00:26:23,740 --> 00:26:26,560

And it is going out with this value to the screen.



380

00:26:26,590 --> 00:26:32,470

So now it's going to execute this line of code that taps operator is going to be assigned to the current



381

00:26:32,470 --> 00:26:33,520

operator.



382

00:26:33,560 --> 00:26:36,260

The operator is the equal operator.



383

00:26:36,610 --> 00:26:38,300

So now it's going to.



384

00:26:38,460 --> 00:26:40,360

It's going to be assigned to the current operator.



385

00:26:40,380 --> 00:26:49,410

If we execute this line of code so it is the current operator is equal let's resume the app.



386

00:26:49,420 --> 00:26:51,460

So now you can see number seven here.



387

00:26:51,460 --> 00:26:53,260

So now you have the number seven.



388

00:26:53,290 --> 00:26:56,220

Number seven multiply it.



389

00:26:56,260 --> 00:26:58,890

I just click on clicked on the multiplied operator.



390

00:26:59,080 --> 00:27:01,310

So it is current operator is not equal to.



391

00:27:01,320 --> 00:27:04,460

So it's not because the current operator is an equal operator.



392

00:27:04,660 --> 00:27:07,960

So let's say this line of code now is going to execute this line.



393

00:27:08,010 --> 00:27:17,070

But if current number is not equal to an empty string value it is to cut the value of the current number



394

00:27:17,080 --> 00:27:19,090

is actually an empty string value.



395

00:27:19,120 --> 00:27:20,590

So there is something wrong here.



396

00:27:20,680 --> 00:27:23,350

This condition here is going to be failed.



397

00:27:23,500 --> 00:27:31,560

If I execute this line of code now we can see that the statement here didn't execute because if it would



398

00:27:31,710 --> 00:27:38,560

if the else statement did execute the empty string value of the current operator is going to be assigned



399

00:27:38,560 --> 00:27:44,150

to this number that live and that's where the actual park would occur.



400

00:27:44,590 --> 00:27:51,520

Now you can see that because these statements now didn't actually secured it's going to assign the trapped



401

00:27:51,610 --> 00:27:57,450

operator to the current operator that have the approach top multiply OK.



402

00:27:57,950 --> 00:28:04,640

I said that 7 multiplied the top of Rotary's multiply and the tapped operator is going to be assigned



403

00:28:04,640 --> 00:28:06,050

to the current operator.



404

00:28:06,050 --> 00:28:15,150

So if I can step over now we can see the current operators multiply so let's resume the 7 multiply by



405

00:28:15,960 --> 00:28:17,010

2.



406

00:28:17,370 --> 00:28:19,970

If you click on these are equal operator here.



407

00:28:19,980 --> 00:28:25,890

Now again it's going to check this condition if current operator is not equal to not it's not the value



408

00:28:25,890 --> 00:28:28,070

of the current operator is multiply.



409

00:28:28,320 --> 00:28:28,920

OK.



410

00:28:29,120 --> 00:28:36,480

So that over and here it is if current number is not equal to an empty string value it's not because



411

00:28:36,570 --> 00:28:39,000

now the value of that number is number two.



412

00:28:39,000 --> 00:28:42,330

I clicked on the number two I and this number two.



413

00:28:42,360 --> 00:28:45,880

So the value of that kind of number is to step over.



414

00:28:46,200 --> 00:28:49,740

And here it says current number is going to be assigned to the string number.



415

00:28:49,830 --> 00:28:50,190

Right.



416

00:28:50,190 --> 00:28:54,690

So number two is going to be assigned to this variable string number that's right and the value of the



417

00:28:54,690 --> 00:28:56,350

kind of number is going to be emptied.



418

00:28:56,670 --> 00:29:01,320

And so each kind of operator which is going to be a multiplication operator and it's going to stick



419

00:29:01,320 --> 00:29:09,050

with this line of code the string number at left is seven and string number that's right is number two.



420

00:29:09,050 --> 00:29:12,460

The result is going to be assigned to the calculation result number 14.



421

00:29:12,650 --> 00:29:18,880

So here is going to as I assign the number 14 to this string number at live step over.



422

00:29:19,040 --> 00:29:21,900

And the value is going to be outfitted to the screen.



423

00:29:22,310 --> 00:29:29,640

So now the trapped operator which is actually the equal operator is now going to be assigned to this



424

00:29:29,660 --> 00:29:31,480

current operator.



425

00:29:31,510 --> 00:29:33,620

So is that over.



426

00:29:33,670 --> 00:29:35,790

And now if I step over again.



427

00:29:35,790 --> 00:29:37,720

So let's resume resumed.



428

00:29:37,740 --> 00:29:38,730

And now we can see.



429

00:29:38,730 --> 00:29:44,280

Let me show you the emulator so you can see that number 14 is output to the screen and our application



430

00:29:44,280 --> 00:29:45,100

didn't crash.



431

00:29:45,120 --> 00:29:46,610

So I can number 14.



432

00:29:46,890 --> 00:29:55,830

So let me just with this breaking point aren't in order to show you that the bug is actually killed



433

00:29:55,880 --> 00:29:58,670

and we can run the app smoothly without any error.



434

00:29:58,670 --> 00:30:14,640

So five minus three equal number two four so multiplied by nine equals 18 divided by three equal six.



435

00:30:14,660 --> 00:30:17,260

So you can see that that application works fine.



436

00:30:17,460 --> 00:30:17,970

OK.



437

00:30:18,290 --> 00:30:20,360

So that's enough for this tutorial.



438

00:30:20,450 --> 00:30:26,090

And in the next story we're going to work on this clear pattern so that they never spot it is actually



439

00:30:26,120 --> 00:30:32,930

tapped or clicked everything on the screen of this for example the text results that Tastee calculations



440

00:30:32,960 --> 00:30:38,540

everything should be clear and the user and the user can actually start calculating from New.



441

00:30:38,540 --> 00:30:40,280

So thank you very much for watching.



442

00:30:40,310 --> 00:30:44,960

If you have any questions please support the discussion in the course and then I will do my best to



443

00:30:44,960 --> 00:30:46,300

answer all of your questions.



444

00:30:46,490 --> 00:30:48,340

I'll see you in the next tutorial.