1

00:00:00,480 --> 00:00:04,590

An inline 20 I decided to output that value to the concert.



2

00:00:04,740 --> 00:00:05,860

So this is that's what DO.



3

00:00:05,930 --> 00:00:07,480

OK number 56.



4

00:00:07,590 --> 00:00:08,610

So what's going on here.



5

00:00:08,610 --> 00:00:13,670

So whenever we actually run our project it's going to actually execute this method here.



6

00:00:13,670 --> 00:00:14,640

This main if it.



7

00:00:14,700 --> 00:00:19,340

So inside of this method we are creating an object from this tiger class card.



8

00:00:19,350 --> 00:00:20,520

My second tiger.



9

00:00:20,520 --> 00:00:21,090

OK.



10

00:00:21,270 --> 00:00:27,690

In Line 14 and it's going to actually execute our constructor OK are constructed inside the target class.



11

00:00:27,750 --> 00:00:28,220

So.



12

00:00:28,260 --> 00:00:30,170

So this is our constructor OK.



13

00:00:30,300 --> 00:00:34,920

And then it's going to actually execute these lines of code inside of these constructor.



14

00:00:34,960 --> 00:00:39,480

OK so this is how it's going to actually execute codes inside of our program.



15

00:00:39,480 --> 00:00:39,910

OK.



16

00:00:40,110 --> 00:00:44,980

So now I want to show you another important point about constructors in Java.



17

00:00:45,360 --> 00:00:51,230

So first let me actually comment out these lines of code here.



18

00:00:54,340 --> 00:00:55,080

OK.



19

00:00:55,420 --> 00:01:00,240

And now I want to actually create multiple constructors for my higher class.



20

00:01:00,250 --> 00:01:00,720

OK.



21

00:01:00,790 --> 00:01:06,490

So as you can see here I created two constructors here and another constructor here.



22

00:01:06,520 --> 00:01:10,210

OK so now I want to actually execute all of these constructors.



23

00:01:10,300 --> 00:01:17,080

So I just need to delete these symbols here in order to allow the compiler to execute these lines of



24

00:01:17,080 --> 00:01:17,590

code here.



25

00:01:17,610 --> 00:01:22,340

OK so now I just need to delete these symbols here and here.



26

00:01:22,420 --> 00:01:23,180

OK.



27

00:01:23,440 --> 00:01:24,450

As you can see here.



28

00:01:24,700 --> 00:01:27,770

Now I have actually three constructors.



29

00:01:27,820 --> 00:01:29,560

So now it's showing us an error.



30

00:01:29,680 --> 00:01:33,060

Let's actually hover over the error area and see what's the error.



31

00:01:34,270 --> 00:01:37,310

Duplicate Somerford tiger type Tiger.



32

00:01:37,450 --> 00:01:42,780

So as you can see here we have two constructors with the same name and with no arguments.



33

00:01:42,840 --> 00:01:45,290

OK so this is not right.



34

00:01:45,310 --> 00:01:53,440

We need to actually create a different constructor and this one in order to allow the compiler to execute



35

00:01:53,440 --> 00:01:54,600

these lines of code here.



36

00:01:54,610 --> 00:01:55,040

OK.



37

00:01:55,120 --> 00:02:02,150

We cannot create duplicate constructivists with the same name and with the same argument type.



38

00:02:02,290 --> 00:02:08,650

So here I want to specify that this constructor is going to accept an argument data type of my argument



39

00:02:08,680 --> 00:02:12,680

is it and the name of my argument is not a.



40

00:02:13,180 --> 00:02:13,840

OK.



41

00:02:14,230 --> 00:02:19,270

And then I want to add this number here to the value of my argument.



42

00:02:19,270 --> 00:02:22,390

OK so 56 plus number a.



43

00:02:22,800 --> 00:02:23,680

OK.



44

00:02:24,010 --> 00:02:28,840

And now as you can see we've got three different constructors inside the tiger class.



45

00:02:28,850 --> 00:02:36,820

OK so this is our first constructor and this is our default constructor and this is our second constructor.



46

00:02:36,970 --> 00:02:45,340

This constructor accepts two arguments so that we can actually pass two values to the constructor and



47

00:02:45,520 --> 00:02:48,130

the first constructor is this constructor.



48

00:02:48,130 --> 00:02:55,930

This constructor accepts one argument and then here in line 19 you are actually adding this number here



49

00:02:55,930 --> 00:02:59,560

56 to the value of the argument here not a.



50

00:02:59,710 --> 00:03:05,650

And then we are actually assigning the result of this operation here to our speed instance valuable



51

00:03:06,220 --> 00:03:10,720

and in line 20 you are actually outputting that value to the console OK.



52

00:03:10,990 --> 00:03:16,980

So inside the main class now as you can see here I want to actually run my project and see what happens.



53

00:03:16,990 --> 00:03:22,940

So if I run my project now as you can see this is the value that is output to the console.



54

00:03:23,110 --> 00:03:25,590

This is our default constructor OK.



55

00:03:25,930 --> 00:03:32,400

So what's going on here as you can see here we didn't actually pass any values to the constructor here.



56

00:03:32,410 --> 00:03:33,460

OK.



57

00:03:33,530 --> 00:03:40,210

Now in line 14 inside the main class and inside the main Mefford we are actually creating an object



58

00:03:40,240 --> 00:03:44,370

from this tiger class and the name of our object is my second tiger.



59

00:03:44,380 --> 00:03:44,790

OK.



60

00:03:44,790 --> 00:03:48,410

Of an approach AirTrans first is going to actually execute this main method.



61

00:03:48,430 --> 00:03:48,980

Okay.



62

00:03:49,240 --> 00:03:54,800

And then as you can see here in say the main If it is going to actually execute this line of code here.



63

00:03:54,970 --> 00:04:00,100

Here we are actually trained to create an object from this tiger class.



64

00:04:00,100 --> 00:04:07,820

So as you can see here it's going to actually execute the default constructor for our tiger class.



65

00:04:07,840 --> 00:04:08,230

OK.



66

00:04:08,230 --> 00:04:11,850

So inside the tile class this is our default constructor.



67

00:04:11,860 --> 00:04:12,310

OK.



68

00:04:12,340 --> 00:04:13,500

As you can see here.



69

00:04:13,630 --> 00:04:15,880

This constructor accepts no argument.



70

00:04:15,880 --> 00:04:22,150

So this is called the default constructor and then inside the constructor I decided to output some values



71

00:04:22,150 --> 00:04:25,920

to the console and that value is this value here as a currency.



72

00:04:25,990 --> 00:04:31,660

And now I want to actually pass two values to my constructor here.



73

00:04:31,900 --> 00:04:37,820

So here I can actually put number three comma number 7 for example.



74

00:04:38,140 --> 00:04:41,020

And as you can see here if I use on my project.



75

00:04:41,020 --> 00:04:43,050

Now let's see what happens.



76

00:04:43,060 --> 00:04:46,330

As you can see it's going to actually output this value to the console.



77

00:04:46,600 --> 00:04:51,520

So this value is the result of execution of this constructor here.



78

00:04:51,670 --> 00:04:52,590

OK.



79

00:04:53,140 --> 00:05:00,700

When we actually create an object from the tile class it's going to execute the constructor that we



80

00:05:00,700 --> 00:05:02,760

created inside the target class here.



81

00:05:02,860 --> 00:05:08,830

OK this is our constructor and this constructor accepts two arguments with the data type.



82

00:05:08,830 --> 00:05:14,740

OK so we passed two numbers as against the two integer numbers through this constructor number three



83

00:05:14,740 --> 00:05:16,380

and number seven.



84

00:05:16,480 --> 00:05:21,070

And then it's going to go inside the constructor and then it's going to actually execute these lines



85

00:05:21,070 --> 00:05:22,040

of code here.



86

00:05:22,150 --> 00:05:28,900

First we created a variable called result and then we tried to actually add the value of these two arguments



87

00:05:28,900 --> 00:05:34,180

together and then be assigned that value to the result variable.



88

00:05:34,360 --> 00:05:38,530

And that in line 14 we decided to output that value to the console.



89

00:05:38,690 --> 00:05:42,450

Number three plus number seven is number 10.



90

00:05:42,630 --> 00:05:43,380

Okay.



91

00:05:43,810 --> 00:05:49,990

And now as you can see our first constructor accepts one argument as you can see here.



92

00:05:49,990 --> 00:05:53,210

So let's actually pass only one value here.



93

00:05:53,310 --> 00:05:55,550

And let's run our project again.



94

00:05:55,570 --> 00:06:00,210

So as you can see here it's going to output this value to the console number 59.



95

00:06:00,400 --> 00:06:06,130

So as you can see here I passed a number of free to this constructor and then it can actually execute



96

00:06:06,580 --> 00:06:07,920

this constructor here.



97

00:06:08,070 --> 00:06:12,630

OK this constructor accepts only one argument with the data type.



98

00:06:12,640 --> 00:06:17,950

So I passed number three which is an integer number two this constructor here.



99

00:06:18,100 --> 00:06:23,410

And then it's going to go inside of this constructor and that it's going to execute these lines of code



100

00:06:23,410 --> 00:06:24,940

here in line 19.



101

00:06:24,970 --> 00:06:31,580

We tried to actually add number 56 to the value of the number a argument.



102

00:06:31,690 --> 00:06:35,940

So the value of the non argument is free as you can see here.



103

00:06:35,940 --> 00:06:44,940

So 56 plus free is 59 and then it's going to assign that value to this instance variable and then it's



104

00:06:44,940 --> 00:06:47,220

going to actually output that value to the concert.



105

00:06:47,340 --> 00:06:50,580

So this value is the value of this instance of it.



106

00:06:50,820 --> 00:06:57,120

And inside the main class if you want to actually access the value of this instance variable and output



107

00:06:57,210 --> 00:07:05,390

that that's value to the console I'll just type in here system that out at Princeton and then inside



108

00:07:05,390 --> 00:07:08,440

the prentices I can't just refer to the name of my object.



109

00:07:08,470 --> 00:07:14,890

My second Tiger does get speed and then I need to put in a semi-colon at the end of my statement.



110

00:07:15,040 --> 00:07:20,390

So now if I run on my project has again satisfied you again is output to the console OK.



111

00:07:20,410 --> 00:07:23,850

This value is the value of the spit instance variable of DS.



112

00:07:23,920 --> 00:07:25,450

My second Tigard object.



113

00:07:25,480 --> 00:07:26,140

OK.



114

00:07:26,350 --> 00:07:32,590

So now if I want to actually create another object from the tiger class here as you can see I just need



115

00:07:32,590 --> 00:07:41,020

to refer to the name of my class tiger and the name of my object is my first object my first tiger.



116

00:07:41,430 --> 00:07:42,180

OK.



117

00:07:42,250 --> 00:07:48,580

And then I need to put in an assignment operator here and then I need to put in this new word and then



118

00:07:48,610 --> 00:07:52,220

again I need to refer to the name of my class here.



119

00:07:52,330 --> 00:07:58,270

So here I actually use the autocomplete feature of the eclipse by pressing on the control key plus the



120

00:07:58,570 --> 00:08:00,310

space key on my keyboard.



121

00:08:00,400 --> 00:08:03,520

As you can see it's going actually comment as these are free options.



122

00:08:03,520 --> 00:08:06,370

The first one is the constructor.



123

00:08:06,370 --> 00:08:08,170

Without no argument.



124

00:08:08,170 --> 00:08:15,310

The second is a constructor with one argument and the first one is constructed with two arguments.



125

00:08:15,340 --> 00:08:18,840

OK we can actually choose between these free arguments.



126

00:08:18,840 --> 00:08:23,740

For example if I choose this one now I need to actually passing two values.



127

00:08:23,740 --> 00:08:25,390

For example number three.



128

00:08:25,810 --> 00:08:27,010

And number two.



129

00:08:27,220 --> 00:08:30,370

And then I need to put in a semi-colon at the end of my statement.



130

00:08:30,580 --> 00:08:35,620

And now if I on my project as you can see this value is out with the console number 5.



131

00:08:35,620 --> 00:08:38,030

So number three plus number two is five.



132

00:08:38,250 --> 00:08:38,530

OK.



133

00:08:38,530 --> 00:08:42,250

As you can see here this constructor accepts two arguments.



134

00:08:42,280 --> 00:08:49,860

And here we are actually adding the value of the first argument to the value of the second argument.



135

00:08:49,870 --> 00:08:52,120

And we are actually out with that's why they go to the concert.



136

00:08:52,120 --> 00:08:55,570

So this value is the result of execution of this constructor here.



137

00:08:55,570 --> 00:08:56,110

OK.



138

00:08:56,170 --> 00:09:00,870

I can't even actually pass one value to this constructor for example number two.



139

00:09:00,890 --> 00:09:05,510

And if I run my project now as you can see it's going to output this value to the console.



140

00:09:05,620 --> 00:09:09,790

So this value is the result of execution of this constructor here.



141

00:09:10,060 --> 00:09:16,560

As you can see here number 56 plus number 2 is number 58 as you can see here.



142

00:09:16,570 --> 00:09:17,180

OK.



143

00:09:17,470 --> 00:09:23,800

And I can even actually pass no values to the constructor and if I get on my project as you can see



144

00:09:23,800 --> 00:09:25,810

it's going out with this value to the console.



145

00:09:25,960 --> 00:09:27,460

This is a default constructor.



146

00:09:27,460 --> 00:09:27,970

OK.



147

00:09:28,030 --> 00:09:35,230

So hopefully that makes sense and I think that's enough for constructor's in this tutorial and in the



148

00:09:35,230 --> 00:09:36,670

other sections of this course.



149

00:09:36,700 --> 00:09:41,440

I'll talk more about constructor's in terms of other important concepts of d'Artois.



150

00:09:41,440 --> 00:09:42,040

OK.



151

00:09:42,220 --> 00:09:43,710

So for now it's enough.



152

00:09:44,030 --> 00:09:49,430

And if you have any questions about these constructivists please post the discussion in the course.



153

00:09:49,690 --> 00:09:53,980

And thanks very much for watching and I'll see you in the next tutorial.