WEBVTT 00:00.440 --> 00:03.860 I welcome you back again to another video lecture in PHP. 00:03.860 --> 00:09.380 And in this video lecture I'll go ahead and tissue about constructors in PHP. 00:16.040 --> 00:22.610 So we have entered into classes and objects and in the previous lecture we are able to deal with these. 00:22.610 --> 00:25.880 We created a class called car. 00:25.880 --> 00:27.950 And we're able to model that class. 00:27.950 --> 00:30.620 And we created the attributes of that class. 00:30.620 --> 00:32.510 And we're able to create the object. 00:32.510 --> 00:38.300 And then we use those attributes of the class to be able to model the car. 00:38.900 --> 00:40.490 So I can see. 00:40.490 --> 00:45.770 And you can also see that we have this car K1 and K2 right in here. 00:45.800 --> 00:49.790 So created two objects of the car which is K1 and K2. 00:49.820 --> 00:54.110 And now we are talking about constructor and what is constructor. 00:54.200 --> 01:03.560 So constructor is a a piece of information or a function that is right inside the class which you just 01:03.570 --> 01:08.040 created, and that it can always be called whenever you create. 01:08.070 --> 01:09.810 Objects of that class. 01:09.810 --> 01:15.300 So a constructor helps you to give more information to your object. 01:15.330 --> 01:17.670 Now go ahead and say this is a class. 01:17.670 --> 01:20.670 And right inside this class I'm going to create. 01:20.700 --> 01:25.440 A function and any function I create here is going to be called a constructor. 01:25.440 --> 01:27.360 So this is a function. 01:27.360 --> 01:33.720 And when you create that function you're going to give two underscore for that to be a constructor. 01:33.720 --> 01:38.850 So what are you going to do right now is create underscore for song underscore second one. 01:38.850 --> 01:43.470 And then you go ahead and give constructor. 01:43.500 --> 01:48.090 So you call construct and you don't call that constructor. 01:48.120 --> 01:52.920 Just put it construct and then put in the parentheses. 01:52.920 --> 01:55.860 And then go ahead and put open up close braces. 01:55.860 --> 02:00.540 And whatever you write in here will be called out anytime you call this. 02:00.540 --> 02:03.990 So if I go ahead and remove this then go ahead and remove this equal. 02:03.990 --> 02:08.220 And then right in here and go ahead Unquiet and equal something. 02:08.220 --> 02:12.780 Let me go on and say we created. 02:15.300 --> 02:15.690 Okay. 02:15.840 --> 02:19.140 So we created new cars because there's only just one car. 02:19.170 --> 02:20.940 We created new cars. 02:20.940 --> 02:25.620 And I'm going to put this put a break tag so it can be able to move to the next line. 02:25.770 --> 02:26.760 The semicolon at the end. 02:26.760 --> 02:27.840 And save this. 02:27.870 --> 02:29.850 Now let's go ahead and refresh this. 02:29.910 --> 02:32.610 We've created new cars and we created new cars. 02:32.610 --> 02:40.290 So I told you that constructor is a piece of information or a function which you create inside a class. 02:40.290 --> 02:47.760 And whenever you call an object or whenever you create an object, that's constructor is being called. 02:47.760 --> 02:53.100 What happens here is that the first object you created here, called the constructor, and the second 02:53.130 --> 02:56.100 object you created is called this constructor. 02:57.420 --> 03:02.400 And just like our normal functions, when we created functions, you can pass any information into your 03:02.400 --> 03:03.180 constructors. 03:03.210 --> 03:06.420 Then go ahead and see that here we have a name. 03:06.450 --> 03:08.550 Let's go ahead and say we. 03:08.620 --> 03:12.340 this guy had to put this to be a name or what? 03:12.340 --> 03:14.020 You have a name already for the car. 03:14.050 --> 03:17.920 This car had and say we give this company. 03:18.520 --> 03:18.820 All right. 03:18.850 --> 03:19.330 So let's go. 03:19.330 --> 03:22.810 That's the company name and the companies that make this. 03:22.810 --> 03:30.550 So what I'm going to do is I will go ahead and let me comment this so that this will not be able to 03:30.550 --> 03:30.880 show. 03:30.880 --> 03:39.730 And then I want to echo the company that make that go ahead and say company and put a semicolon at the 03:39.730 --> 03:40.150 end. 03:40.180 --> 03:43.240 Now I will go to the first car and I will give the company. 03:43.360 --> 03:45.850 Go ahead and pass in the name of the company. 03:45.850 --> 03:50.560 And uh, I don't actually the company is still there, so I don't know how to put in there. 03:50.590 --> 03:52.960 Let's go ahead and say is George. 03:53.050 --> 03:53.920 All right. 03:53.920 --> 03:56.230 And, uh, that is a company name. 03:56.230 --> 03:59.500 And the next one is Nissan is already is already a company. 03:59.500 --> 04:01.150 So I'm gonna say Steve. 04:01.390 --> 04:03.190 And now let's go ahead and save this. 04:03.190 --> 04:10.870 So if we go ahead and refresh this because we input in this the company name. 04:10.870 --> 04:15.020 So it will always go here and check out whatever the first object has. 04:15.050 --> 04:16.430 And that will be printed out. 04:16.430 --> 04:19.130 And whatever the second object has that will be printed out. 04:19.160 --> 04:21.320 Now let's go ahead and refresh this and check it out. 04:21.590 --> 04:28.070 Judge Steve so you can actually go ahead and put a break tag inside so it can move to the next line. 04:28.820 --> 04:33.500 So you can see that the very first object we created here called this constructor. 04:33.500 --> 04:37.460 And the second object we have here called this constructor. 04:37.460 --> 04:39.770 And that is why we have got Steve. 04:39.770 --> 04:47.000 So a constructor is just an a function or piece of information which you input inside the class. 04:47.000 --> 04:51.680 And whenever the object is being called it goes on to call the constructor. 04:51.710 --> 04:58.280 Now you can see how many lines of code it takes us to write this, to create these two cars, or to 04:58.310 --> 04:59.750 model the two cars. 04:59.750 --> 05:05.210 So the constructor can help us to limit these lines of code because it's really too long. 05:05.240 --> 05:13.160 So how can we be able to use constructor to model this two lines of code, or to fail to model these 05:13.160 --> 05:13.790 two cars? 05:13.850 --> 05:16.700 How are we able to use this constructor to model these two cars? 05:16.730 --> 05:21.110 In order to make this to be more simpler and more easy for us. 05:21.140 --> 05:23.000 Now let's go ahead and check it out. 05:24.080 --> 05:32.750 So now what I'm going to do is I will go ahead and pass in all the attributes of everything we have 05:32.750 --> 05:34.160 here, right inside this constructor. 05:34.190 --> 05:38.240 So let me go ahead and get rid of this so that we can start this. 05:38.270 --> 05:41.870 Now if I want to do this I should refactor each of these. 05:41.900 --> 05:47.150 Let's say if I'm working with car one, I should refer to it as the current object I'm working with. 05:47.180 --> 05:53.030 And if I want to refer to this as the current object, I'm going to use this. 05:53.030 --> 05:58.820 So this keyword actually specifies the current object I'm working with. 05:58.850 --> 06:06.710 So if I'm working on the car one that means this will always refer to the current object. 06:06.710 --> 06:10.820 So D then I'll go ahead and copy the name. 06:10.820 --> 06:13.100 And then I'm going to pass this one in here. 06:13.100 --> 06:16.770 And before then I should go right inside idea. 06:16.800 --> 06:19.470 I'm going to remove this company in which we put in here. 06:19.470 --> 06:28.860 And then I'm going to set in the variables which I did here for k1, k2, k and the others I did for 06:28.860 --> 06:30.180 k1 and K2. 06:30.210 --> 06:34.830 Then we'll pass in the name variable, the variable and the color variable. 06:34.830 --> 06:39.690 And for me to do that I say I can create a new one called name. 06:40.560 --> 06:49.590 Then with semicolon and create another one called car E with semicolon. 06:49.590 --> 06:54.330 Under the next one is a car color. 06:54.360 --> 06:56.460 Now I go ahead. 06:56.460 --> 07:06.180 I say car name is equal to then car name kind of at the end. 07:06.180 --> 07:11.250 And then we also refer to the next one within this keyword. 07:12.960 --> 07:14.580 That is the year. 07:15.960 --> 07:19.980 Go ahead and say this is equal to Car. 07:20.220 --> 07:25.680 You put a semicolon at the end and in the next one isn't this keyword. 07:25.680 --> 07:30.900 So that anyone we are working on, we always know either car one or cat two. 07:30.930 --> 07:38.490 So this column and this is equal to car column. 07:38.610 --> 07:44.850 Now you see I always refer to each of these variable because you remember in the when we call the church 07:44.850 --> 07:48.540 city it went on and get whatever that we have read in here. 07:48.540 --> 07:56.250 So what it means is that any of the parameters you pass in here, the name, the year and the color, 07:56.280 --> 07:58.770 you are going to pass that into your object. 07:58.770 --> 08:03.390 So I'm going to get rid of this, uh, church, Steve or George I put in here. 08:03.390 --> 08:07.560 And the very first one, the name is Toyota. 08:07.560 --> 08:10.530 So for cow I'm going to pass in Toyota. 08:10.650 --> 08:11.910 And the year. 08:11.910 --> 08:17.430 So the year here is a string I can actually go ahead and pass that as an integer which is 2030. 08:17.430 --> 08:22.180 And in the next one is uh the black which is the a color. 08:22.210 --> 08:24.910 Go ahead and pass in that. 08:24.910 --> 08:27.670 Now I can get rid of this. 08:27.700 --> 08:28.660 Go ahead and remove this. 08:28.660 --> 08:31.540 So I've done justice to cat one. 08:31.540 --> 08:34.180 So for cat two I'll go ahead and get rid of this. 08:34.180 --> 08:38.800 So for the name of the card I'll go ahead and pass in this one. 08:40.120 --> 08:45.580 And the year is 2070. 08:45.580 --> 08:48.520 And the color I'll go ahead and copy this. 08:48.520 --> 08:52.690 So the reason why I'm doing this step by step is for you to know what we are working on. 08:52.690 --> 08:55.750 We are not bringing something new is everything we have in here. 08:55.780 --> 09:04.810 So now I'll get rid of this and the what I need to do now is now I have been able to reduce what we 09:04.810 --> 09:07.480 have here into just two lines of code. 09:07.480 --> 09:11.380 So I'll go ahead and, uh, equal any one. 09:11.380 --> 09:15.460 So for car one okay. 09:15.490 --> 09:18.520 No, this is our car one. 09:18.550 --> 09:23.860 Then we go ahead and, uh, print that out. 09:23.860 --> 09:29.930 So if we want to print out the name of the car, can go ahead and say car one name. 09:30.800 --> 09:37.970 Okay, so car one name and end and save this and this kind of refresh and check it out Toyota. 09:38.210 --> 09:40.460 So you can see I'm able to do the same thing. 09:40.460 --> 09:43.490 So if I change this to car two and save this. 09:43.520 --> 09:45.590 I'll refresh this I have Nissan. 09:45.770 --> 09:52.820 So if I change this to maybe the year again I save this. 09:52.850 --> 09:56.900 I refresh this 2017 for car two. 09:57.620 --> 10:02.930 So let me go ahead and say I want to modify the car. 10:02.960 --> 10:10.760 One and I'm going to say I want to change the name of car one again and say car okay. 10:10.850 --> 10:11.810 Car one. 10:12.260 --> 10:17.210 And uh, let that be equal to okay. 10:17.210 --> 10:20.060 We have the let's go ahead and see anything. 10:20.090 --> 10:25.610 We can actually change that is equal to 4050. 10:25.610 --> 10:28.280 So within the year 1457. 10:28.280 --> 10:28.640 This. 10:28.640 --> 10:35.510 And if I should go ahead and change this to count, go ahead and save this and refresh. 10:35.570 --> 10:38.180 You can see I have 1450 words in here. 10:38.270 --> 10:40.940 So I can actually modify that down here. 10:40.940 --> 10:47.810 So the aim of using constructor is to help us to be able to give more information to an object. 10:47.810 --> 10:54.530 And in that case, it also helps us to reduce the bunch of code we write on that object. 10:54.530 --> 10:56.600 So you can see if I should go ahead and remove. 10:56.750 --> 10:57.860 Let me get rid of this. 10:57.860 --> 11:00.170 And I have those two lines of code here. 11:00.170 --> 11:02.810 And if I refresh this it has gone back to 2030. 11:02.810 --> 11:09.350 And if you change the color of this guy and I change the color and that is black. 11:09.980 --> 11:16.640 So you can see the constructor plays a very big role, a vital role in PHP and is very important. 11:16.640 --> 11:17.570 You know about that. 11:17.570 --> 11:19.010 So why had I checked this out. 11:19.010 --> 11:19.850 Practice with it. 11:19.850 --> 11:23.630 And if you have any question, please go ahead and use the question and answer section. 11:23.630 --> 11:26.120 And I'm going to get back to you as soon as possible. 11:26.150 --> 11:27.050 Thank you so much. 11:27.050 --> 11:30.020 And I'm going to see you in the next video lecture.