WEBVTT 00:00.830 --> 00:05.690 In this lecture you will learn about the references in C plus plus. 00:05.720 --> 00:11.000 References are safer, more convenient versions of pointers. 00:11.030 --> 00:19.730 You declare references with this ampersand declaration here um, appended to the type name. 00:19.730 --> 00:26.380 So references cannot be assigned to null and they cannot be reseated or resigned. 00:26.390 --> 00:31.430 So these characteristics eliminate some bugs endemic to pointers. 00:31.430 --> 00:36.680 So the syntax for dealing in references is much cleaner than for pointers. 00:36.680 --> 00:44.330 So rather than using the member of Pointer and the reference operators, you use references exactly 00:44.330 --> 00:47.600 as if they are of the pointer to type. 00:47.600 --> 00:48.290 So. 00:49.040 --> 00:56.360 Now I want to create some, uh, firstly, we going to create the ad here outside of the main function, 00:56.390 --> 01:02.720 of course we're going to create the void ad year, ad year. 01:02.720 --> 01:11.420 So we will fill this function after creating our struct, which we're going to create a struct here 01:11.420 --> 01:12.590 named the. 01:13.650 --> 01:14.790 World clock. 01:14.820 --> 01:16.980 World clock here. 01:18.210 --> 01:23.220 Or let's make name it for the year here. 01:23.280 --> 01:24.540 World year. 01:25.290 --> 01:33.510 And in this racket, we're going to have the integer type integer variable named year here. 01:33.660 --> 01:39.420 And we're going to use the getter and setter methods to assign this year something. 01:40.290 --> 01:46.170 First, let's assign use getter method here integer. 01:47.540 --> 01:48.650 We will make made. 01:48.740 --> 01:55.430 We made this integer because the getter method, as you know, returns something on it. 01:55.430 --> 01:58.250 So in this case, we're going to return the integer number. 01:59.250 --> 02:00.210 Uh, integer. 02:00.240 --> 02:01.230 Get here. 02:01.260 --> 02:02.130 Here. 02:02.250 --> 02:05.460 And return. 02:05.460 --> 02:07.850 Return here. 02:08.110 --> 02:08.830 Here. 02:09.480 --> 02:12.590 And we're going to use the setter method as well. 02:12.600 --> 02:18.120 The setter method can be just, uh, void in this case. 02:18.870 --> 02:20.370 Uh, set. 02:20.880 --> 02:24.840 Set here and integer. 02:26.590 --> 02:29.080 The temporary year here. 02:30.140 --> 02:30.950 And. 02:32.820 --> 02:36.600 Year equals to year. 02:42.300 --> 02:45.030 And then we're going to let's create an. 02:46.010 --> 02:47.270 This function here. 02:50.300 --> 02:50.960 Here. 02:51.350 --> 02:53.060 So firstly. 02:54.250 --> 03:03.550 We're going to this add parameter will get the struct type name the world year and as a parameter. 03:03.640 --> 03:12.310 So world year this ampersand here and uh, for example my. 03:13.030 --> 03:15.400 For X year here. 03:16.500 --> 03:17.490 And then. 03:19.140 --> 03:20.550 Uh, x here. 03:20.790 --> 03:21.530 X here. 03:21.540 --> 03:23.100 Dot set here. 03:23.750 --> 03:24.190 Here. 03:24.240 --> 03:24.960 And x here. 03:24.960 --> 03:25.830 That. 03:25.830 --> 03:28.710 Get here plus one. 03:29.190 --> 03:33.450 That's because we're going to increment our the year. 03:34.390 --> 03:39.850 Uh, by one, whenever we execute this function here. 03:39.850 --> 03:43.030 And let's come to the main function here. 03:43.460 --> 03:44.440 Uh, here. 03:44.500 --> 03:46.030 My world. 03:46.420 --> 03:46.990 World. 03:47.020 --> 03:47.310 Here. 03:47.320 --> 03:47.650 Here. 03:47.770 --> 03:49.120 World year. 03:49.240 --> 03:50.800 World year. 03:51.490 --> 03:53.680 Um, Earth, for example. 03:53.680 --> 03:56.710 My earth here. 03:57.670 --> 04:00.230 We're going to print something on the screen. 04:00.440 --> 04:01.750 Screen here. 04:01.750 --> 04:06.310 In this case, we're going to print the variable named year. 04:06.610 --> 04:11.430 The year is the year is decimal. 04:11.440 --> 04:19.210 I will explain all of these codes one by one later after we have done this project here in this lecture. 04:20.350 --> 04:21.070 So. 04:21.790 --> 04:23.680 Clock Dot, Get here. 04:24.810 --> 04:29.700 Clock that actually not clock my earth, that gate here. 04:30.330 --> 04:39.450 And after that we're going to call the adhere function and pass my earth as a parameter. 04:40.180 --> 04:45.730 And after that we will print the print this again. 04:47.710 --> 04:48.340 Here. 04:51.330 --> 04:54.120 And let's run our program now. 04:54.780 --> 05:01.710 As you can see here, this returned first to zero and then one which this means our variable incremented 05:01.710 --> 05:02.450 by one. 05:02.460 --> 05:03.630 So. 05:04.670 --> 05:15.740 Uh, so for example, if I want to just return the 2023, in this case, I have to assign my Earth dot 05:15.800 --> 05:25.310 set year 2020 22 and it will increment the year two by one. 05:25.310 --> 05:32.870 So now I want to talk about these codes one by one, what we did in the technical manner of this. 05:32.870 --> 05:38.630 So you the firstly, you declare the world year argument as here. 05:39.690 --> 05:43.320 As a reference using the ampersand. 05:44.060 --> 05:47.240 Rather than asterisk here, as you can see here. 05:47.270 --> 05:56.320 Then within a add year, you use the X year as if it were of the type world year. 05:56.330 --> 06:01.310 So there's no need to use a clumsy dereference and pointer to reference operators. 06:01.520 --> 06:06.380 First, you print the value as a value of year here. 06:08.200 --> 06:16.240 And the next, uh, at the call site, you pass the, uh, my Earth object directly into. 06:17.290 --> 06:18.130 Here. 06:18.160 --> 06:22.510 Add the year and there's no need to take its address. 06:22.540 --> 06:30.310 Finally, you print the value of year again to illustrate that it has incremented. 06:32.170 --> 06:33.490 As you can see here.