WEBVTT 00:00.540 --> 00:01.320 In C plus. 00:01.320 --> 00:06.180 Plus the code is executed from the main function. 00:06.750 --> 00:11.550 So the function itself is a collection of statements to perform a specific task. 00:11.580 --> 00:21.000 As a result of this, a program in C plus plus has to contain at least one function named Main. 00:21.810 --> 00:28.560 So this code is the simplest program in C plus plus that will be successfully compiled and run. 00:28.560 --> 00:33.510 So suppose this code is saved in the main dot cpp file. 00:33.510 --> 00:40.640 We can compile the code using the g plus plus compiler by running the command here, g plus plus G, 00:40.650 --> 00:46.080 sym or main.cpp here and then a dot exe. 00:46.110 --> 00:50.600 So whenever we compile something, we're going to get the a dot exe file. 00:50.610 --> 00:57.630 So if we make it here, here, and as you can see here, our file is created right here. 00:57.630 --> 01:00.360 So now we're going to execute it a dot exe. 01:00.450 --> 01:06.030 And as you can see, this is our hello world that we executed from here. 01:06.180 --> 01:11.320 So if an error message appears, the output file will be generated automatically. 01:11.340 --> 01:19.050 So if we run this code compiling command in the windows console, we will get a file named a dot exe 01:19.290 --> 01:21.120 as I said earlier. 01:21.120 --> 01:27.880 So however, if we run the command on the bash shells such as Linux or Mac OS, we will get the file 01:27.880 --> 01:30.580 name named a dot out. 01:31.570 --> 01:39.640 So we can specify the output file name using the dot or option dot or option followed by the desired 01:39.640 --> 01:40.010 file name. 01:40.030 --> 01:49.090 For instance, if the command will write like this here Main.cpp dot minus all here and here, we're 01:49.090 --> 01:55.600 going to make it hoxily dot x and now we're going to make it here. 01:55.600 --> 01:55.870 Here. 01:55.870 --> 02:02.170 And as you can see here, our file name named Hoxily dot X is created right here. 02:02.170 --> 02:10.270 So whenever the dot x oops, hoxily dot x, and as you can see here, our file executed without any 02:10.270 --> 02:10.660 problem. 02:10.660 --> 02:15.190 And as you can see, the actual these are the same size of program because they are the same program 02:15.190 --> 02:16.450 but different file name. 02:17.490 --> 02:25.950 So indeed we run the output file by typing a and then pressing enter on the Windows console or by typing 02:25.950 --> 02:28.440 the auxiliary and then enter on a bash shell. 02:28.470 --> 02:34.020 We won't see anything on the console window if we don't have the stdcout here. 02:34.020 --> 02:44.010 So if we will delete that and make it GCC or g++ main.cpp and a dot exe. 02:44.010 --> 02:51.570 And as you can see, we have we see nothing here because we don't set anything to our program cpp file. 02:51.600 --> 02:53.100 To write something on the screen. 02:53.100 --> 02:56.810 So this is why it's not showing anything now. 02:56.820 --> 02:57.720 So. 02:59.090 --> 03:01.490 If a write like this for example. 03:01.880 --> 03:04.940 Integer E integer E here. 03:05.420 --> 03:05.930 STD. 03:07.640 --> 03:08.360 Let's see. 03:08.360 --> 03:08.750 Out. 03:10.320 --> 03:15.480 Please enter an integer value. 03:17.460 --> 03:18.870 And here. 03:19.590 --> 03:20.040 STD. 03:24.410 --> 03:31.460 Seen here is the and we're going to make it to E here and then STD. 03:32.640 --> 03:33.630 See out. 03:33.660 --> 03:35.280 This is the here. 03:36.000 --> 03:40.590 The value you entered is. 03:42.460 --> 03:48.580 Here, and then we're going to, uh, make it the new line. 03:49.270 --> 03:51.130 Stdcout. 03:52.160 --> 03:53.090 And. 03:53.090 --> 03:53.690 And here. 03:53.690 --> 03:54.500 Like this. 03:55.780 --> 03:56.710 So. 03:56.740 --> 03:57.380 Oops. 03:57.400 --> 03:58.000 Uh, the. 03:59.290 --> 04:03.010 Okay, So in here like this, let me check if the. 04:03.920 --> 04:04.430 Okay. 04:05.350 --> 04:06.070 So. 04:07.620 --> 04:11.220 Now let's run our program here. 04:12.110 --> 04:14.270 And save it. 04:15.210 --> 04:24.260 G Plus, plus, plus, plus main.cpp here and a dot xm this is. 04:24.260 --> 04:28.070 And please enter an integer value in this case 99. 04:28.070 --> 04:33.260 And as you can see here, the value is entered is 99. 04:33.260 --> 04:34.700 So this is just a basic example. 04:34.700 --> 04:40.250 So as you can see here, we appended several lines of code so that the program can print to the console 04:40.250 --> 04:42.650 and the user can give an input to the program. 04:42.650 --> 04:48.260 So initially the program displays text that ask the user to input an integer number. 04:48.260 --> 04:54.620 So after the user types, the desired number and then press enter, the program will print that number. 04:54.620 --> 04:58.640 So we will also define a new variable named E here. 04:58.670 --> 05:03.620 So this is the E of the integer data type. 05:03.620 --> 05:09.410 So this variable is used to store the data in integer data format. 05:09.410 --> 05:14.520 So we will talk about the variables and data types in next lecture. 05:14.520 --> 05:19.440 So here and this you can see here and then here. 05:20.690 --> 05:26.090 So suppose we have the same, um, the presenting code as the main dot cpp. 05:26.120 --> 05:32.600 We can compile it using the g plus plus the main dot cpp. 05:32.990 --> 05:35.810 And as you can see here, and run it like this. 05:35.810 --> 05:41.600 And you can also use the arrow here or parameter or in this case we're going to make it. 05:41.600 --> 05:48.910 For example, show number, show number dot exit and show number dot x. 05:48.920 --> 05:54.140 And as you can see here, uh, 77, the value you entered is 77. 05:54.440 --> 06:02.720 Uh, so now we now know that, uh, the print text to the console, we use the Stdcout command and to 06:02.720 --> 06:08.390 give some inputs to the program, we use the STD sin command here. 06:08.390 --> 06:14.630 So in this file we also see the include Iostream at the beginning of the file, it's used to tell the 06:14.630 --> 06:23.010 compiler where to find the implementation of the Stdcout at and std seen here. 06:23.950 --> 06:24.450 Oops. 06:24.460 --> 06:25.060 Yeah. 06:26.650 --> 06:29.200 So um. 06:29.200 --> 06:34.180 And since their implementation in is stated in the iOS stream file. 06:34.180 --> 06:38.050 So if you delete the stream file, you will see errors in this code. 06:38.050 --> 06:43.540 So since they are not the default here, so we need to input output stream here. 06:43.540 --> 06:48.190 So at the very beginning of the file we can see the. 06:49.140 --> 06:55.680 Lines here that begins, For example, actually, let's write some lines and I want to mention it. 06:56.430 --> 07:00.510 Comments here or Main.cpp Command. 07:01.170 --> 07:02.790 Oxley Academy. 07:02.790 --> 07:03.810 So here. 07:06.200 --> 07:08.540 So this is the double slashes. 07:08.540 --> 07:14.060 So this means that a line won't be considered as a code, so the compiler will ignore it. 07:14.060 --> 07:20.240 So it's used to comment or mark an action in the code so that other programmers can understand our code 07:20.270 --> 07:20.750 here. 07:20.750 --> 07:27.260 So if we compile this, you will get the same result because and the same file size because this code 07:27.260 --> 07:29.810 will ignore by the compiler. 07:29.810 --> 07:37.550 So let's actually make this so the writing so much comments like this should increase the file size. 07:37.550 --> 07:37.970 Right? 07:37.970 --> 07:47.780 So main dot CP here and with comments x and there here. 07:47.780 --> 07:54.680 And as you can see here, the show number is without comments, without comments. 07:54.830 --> 07:59.600 But the with comments here is with comments that we will write it like this. 07:59.600 --> 08:07.830 So and as you can see, the file size is same because the compiler isn't compiled this line of code. 08:07.830 --> 08:10.320 So this is just an a comment.