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Now that we've pretty much completed all of the logic and functionality of this

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calculator, it's time to add in the bells and the whistles,

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including adding in the calculator logo and also checking for any bugs.

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Adding the calculator logo is pretty simple.

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You've done this loads of times before.

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All we have to do is import it from the art module,

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and then we're going to print it at the beginning of our calculator function.

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So this way

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when we get to the end and the user wants to start a fresh calculation,

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we'll also show them a logo again. Now the next thing to notice,

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this is a bit of a bug that you might've seen or not.

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But what happens if we try to enter a number with a decimal point?

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Let's say we want to calculate 4.5 multiplied by 2.

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Our program has already crashed

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as soon as I've entered 4.5 and hit enter. As a challenge,

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can you diagnose what went wrong and fix this bug? I'll give you a few seconds

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to pause the video before I give you the 

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solution.

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Alright. Here's the solution.

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The bug goes back to our lesson on datatypes.Notice how it's giving us an error

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and it's pointing to this line

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number 26. Line number 26 takes this input

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which is a string and converts it into an integer. But of course,

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a number with the decimal place shouldn't be converted into an integer.

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We should actually hold it as a floating point number instead. This way

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we're able to perform more accurate calculations.

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So instead of just 4 times 5,

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we can do 4.5 times 5.5, for example.

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So instead of using int here, I'm going to change that to float

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and I'm going to do the same here for num2. Now, when we hit run,

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I can actually perform calculations using numbers with decimal places,

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but I can also use numbers which are whole.

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So let's multiply 2.5 by 2, the answer is 5,

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and you can see that all the numbers are being reported to a greater level of

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accuracy, meaning we have numbers after the decimal point.

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And this is all because we converted that int to a float.

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Now that there's a lot more features that you could add to your calculator.

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You could add a square root capability, you could add exponent capability,

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but the important thing here was really for you to see how functions that

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provide outputs are really useful

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when you come to a more complex program where you can take the output from one

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function call and pass it into the next function

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call as an input.

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So this output can be reused in different parts of the code.

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And this not only allows us to reduce repetition and also make our more reusable

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and more modular,

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but also it gives us the flexibility of performing more actions after a function

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has completed. Now,

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we're going to be using a lot of the concepts that we've learned here today in

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tomorrow's capstone project. A lot of things I've explained,

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including things like the recursion

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where we're calling a function within its own definition or things like setting a

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flag using a wall loop to continue

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some piece of code execution is all going to come in really,

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really handy tomorrow.

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So make sure that if there's anything that you don't understand here

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that you review it and you're comfortable with what the code is doing before you

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proceed. That's all for today and I'll see you tomorrow.