Difference between revisions of "C-and-C++/C2/Functions/English-timed"

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|'''Time'''
 
|'''Time'''
−
 
 
|'''Narration'''
 
|'''Narration'''
−
 
  
 
|-
 
|-
−
| 00.01
+
| 00:01
−
|Welcome to the spoken tutorial on Functions in C and C++
+
|Welcome to the spoken tutorial on '''Functions in C and C++'''.
  
 
|-
 
|-
−
| 00.06
+
| 00:06
 
|In this tutorial we will learn,   
 
|In this tutorial we will learn,   
  
 
|-
 
|-
−
| 00.09
+
| 00:09
−
|What is a function
+
|What is a '''function'''
  
 
|-
 
|-
−
| 00.11
+
| 00:11
−
|Syntax of a function
+
|Syntax of a '''function'''
  
 
|-
 
|-
−
| 00.13
+
| 00:13
−
|Significance of return statement
+
|Significance of '''return statement'''
  
 
|-
 
|-
−
| 00.16
+
| 00:16
 
| We will do this through examples.  
 
| We will do this through examples.  
  
 
|-
 
|-
−
| 00.18
+
| 00:18
 
|We will also see some common errors and their solutions.  
 
|We will also see some common errors and their solutions.  
  
 
|-
 
|-
−
| 00.22
+
| 00:22
 
| To record this tutorial, I am using,  
 
| To record this tutorial, I am using,  
  
 
|-
 
|-
−
| 00.25
+
| 00:25
−
|Ubuntu Operating System version 11.10
+
|'''Ubuntu Operating System''' version 11.10,
  
 
|-
 
|-
−
|00.30
+
|00:29
−
| gcc and g++ Compiler version 4.6.1 .
+
| '''gcc''' and '''g++ Compiler''' version 4.6.1 .
−
 
+
  
 
|-
 
|-
−
|00.35
+
|00:35
−
|Let us start with the introduction to functions
+
|Let us start with the introduction to '''functions'''.
  
 
|-
 
|-
−
|00.39
+
|00:39
−
|A function is a self-contained program executing a specific task.  
+
|A '''function''' is a self-contained program executing a specific task.  
  
 
|-
 
|-
−
| 00.44
+
| 00:45
−
|Every program consists of one or more functions.  
+
|Every program consists of one or more '''functions.'''
  
 
|-
 
|-
−
| 00.49
+
| 00:49
 
|Once executed, the control will be returned back from where it was accessed.  
 
|Once executed, the control will be returned back from where it was accessed.  
  
 
|-
 
|-
−
| 00.55
+
| 00:55
−
|Let us see the syntax for function.  
+
|Let us see the syntax for '''function.'''
  
 
|-
 
|-
−
| 00.59
+
| 00:59
−
|ret-type defines the type of data that the function returns.  
+
|'''ret-type''' defines the type of data that the '''function returns. '''
  
 
|-
 
|-
−
| 01.05
+
| 01:05
−
|fun_name defines the name of the function.  
+
|'''fun_name''' defines the name of the function.  
−
 
+
  
 
|-
 
|-
−
|01.09
+
|01:09
−
|parameters is the list of variable names and their types.  
+
|'''parameters''' is the list of '''variable''' names and their types.  
  
 
|-
 
|-
−
| 01.14
+
| 01:14
−
|We can specify an empty parameter list.  
+
|We can specify an '''empty parameter list'''.  
  
 
|-
 
|-
−
| 01.17
+
| 01:18
−
|This is called as functions without arguments.  
+
|This is called as '''functions without arguments. '''
  
 
|-
 
|-
−
| 01.21
+
| 01:21
−
|And this is called as functions with arguments.  
+
|And this is called as '''functions with arguments. '''
  
 
|-
 
|-
−
|01.27
+
|01:26
−
|Let us see a program using void.  
+
|Let us see a program using '''void. '''
  
 
|-
 
|-
−
|01.29
+
|01:29
 
|I have already typed the program on the editor.  
 
|I have already typed the program on the editor.  
  
 
|-
 
|-
−
|01.32
+
|01:32
 
|So I will open it.  
 
|So I will open it.  
−
 
  
 
|-
 
|-
−
|01.35
+
|01:35
−
|Note that our filename is function.  
+
|Note that our file name is '''function. '''
  
 
|-
 
|-
−
| 01.38
+
| 01:38
−
|And I have saved the file with the extentsion .c
+
|And I have saved the file with the extension '''.c''' (dot c).
  
 
|-
 
|-
−
| 01.43
+
| 01:43
 
|Let me explain the code.  
 
|Let me explain the code.  
−
 
  
 
|-
 
|-
−
| 01.45
+
| 01:45
−
|This is our header file.  
+
|This is our '''header file. '''
  
 
|-
 
|-
−
|01.47
+
|01:47
−
|Before using any function, it must be defined.  
+
|Before using any '''function''', it must be defined.  
  
 
|-
 
|-
−
|01.51
+
|01:51
−
|Here we have defined a function called add.  
+
|Here we have defined a '''function''' called '''add.'''
  
 
|-
 
|-
−
|01.54
+
|01:54
−
|Note that add function is without any arguments.  
+
|Note that '''add function''' is without any '''arguments.'''
  
 
|-
 
|-
−
|01.58
+
|01:58
−
|And the return type is void.  
+
|And the return type is '''void. '''
  
 
|-
 
|-
−
| 02.01
+
| 02:01
 
|There are two types of functions-  
 
|There are two types of functions-  
−
 
  
 
|-
 
|-
−
| 02.03
+
| 02:03
−
| User-defined that is our add function and  
+
| '''User-defined''' that is our '''add function''' and  
  
 
|-
 
|-
−
| 02.06
+
| 02:06
−
| Pre-defined that is printf and main function  
+
| '''Pre-defined''' that is '''printf''' and '''main function '''.
−
 
+
  
 
|-
 
|-
−
| 02.12
+
| 02:12
−
| Here we have initialized a and b by assigning them values as 2 and 3  
+
| Here we have initialized '''a''' and '''b''' by assigning them values as 2 and 3.
  
 
|-
 
|-
−
| 02.19
+
| 02:19
−
| Here we have declared a variable c.  
+
| Here we have declared a variable '''c. '''
  
 
|-
 
|-
−
| 02.21
+
| 02:21
 
|Then we add the values of a and b.  
 
|Then we add the values of a and b.  
  
 
|-
 
|-
−
| 02.24
+
| 02:24
 
|The result is stored in c.  
 
|The result is stored in c.  
  
 
|-
 
|-
−
| 02.27
+
| 02:27
 
|Then we print the result.  
 
|Then we print the result.  
  
 
|-
 
|-
−
| 02.29
+
| 02:29
−
| This is our main function.  
+
| This is our '''main function. '''
  
 
|-
 
|-
−
| 02.32
+
| 02:32
−
|Here we call the add function.  
+
|Here we call the '''add''' function.  
  
 
|-
 
|-
−
| 02.34
+
| 02:34
 
|The addition operation will be performed and the result will be printed.  
 
|The addition operation will be performed and the result will be printed.  
  
 
|-
 
|-
−
| 02.39
+
| 02:39
−
| Now click on Save.
+
| Now click on '''Save.'''
  
 
|-
 
|-
−
| 02.42
+
| 02:42
 
|Let us execute the program.
 
|Let us execute the program.
  
 
|-
 
|-
−
| 02.45
+
| 02:45
−
|Please open the terminal window by pressing Ctrl, Alt and T keys simultaneously.
+
|Please open the terminal window by pressing '''Ctrl, Alt''' and '''T ''' keys simultaneously.
  
 
|-
 
|-
−
| 02.53
+
| 02:53
−
|To compile, type gcc  function dot c  hyphen o  fun
+
|To compile, type '''gcc  function dot c  hyphen o  fun'''.
−
 
+
  
 
|-
 
|-
−
| 03.00
+
| 03:00
−
|To execute, type ./fun  
+
|To execute, type '''./fun''' (dot slash fun).
−
 
+
  
 
|-
 
|-
−
| 03.05
+
| 03:05
−
|We see the output is displayed as Sum of a and b is 5  
+
|We see the output is displayed as '''Sum of a and b is 5 '''.
−
 
+
  
 
|-
 
|-
−
| 03.10
+
| 03:10
 
|Now come back to our program.  
 
|Now come back to our program.  
  
 
|-
 
|-
−
| 03.13
+
| 03:13
−
|Functions contains special identifiers called as parameters or arguments.  
+
|Functions contain special identifiers called as '''parameters''' or '''arguments.'''
  
 
|-
 
|-
−
| 03.20
+
| 03:20
 
|Let us see the same example with arguments.  
 
|Let us see the same example with arguments.  
  
 
|-
 
|-
−
| 03.23
+
| 03:23
 
|I will change a few things here.  
 
|I will change a few things here.  
  
 
|-
 
|-
−
| 03.27
+
| 03:27
−
|Type int add(int a, int b)  
+
|Type '''int add(int a, int b) '''
−
 
+
  
 
|-
 
|-
−
| 03.32
+
| 03:32
−
|Here we have declared a function add.  
+
|Here we have declared a '''function add. '''
−
 
+
  
 
|-
 
|-
−
| 03.36
+
| 03:36
−
|int a and int b are the arguments of the function add.  
+
|'''int a''' and '''int b''' are the '''arguments''' of the function '''add.'''
  
 
|-
 
|-
−
| 03.41
+
| 03:41
−
|Let us delete this.  
+
|Let us delete this.No need to initialize a and b here.  
  
 
|-
 
|-
−
| 03.42
+
| 03:46
−
|No need to initialize a and b here.  
+
|Delete the '''printf '''statement.  
  
 
|-
 
|-
−
| 03.46
+
| 03:49
−
|Delete the printf statement.
+
|Type '''int main() '''
  
 
|-
 
|-
−
| 03.49
+
| 03:52
−
|Type int main()
+
| Let us declare a variable '''sum''' here.
−
 
+
  
 
|-
 
|-
−
| 03.52
+
| 03:54
−
| Let us declare a variable sum here.
+
|Type '''int sum; '''
−
 
+
  
 
|-
 
|-
−
| 03.54
+
| 03:57
−
|Type int sum;  
+
|Then type '''sum = add(5,4); '''
−
 
+
  
 
|-
 
|-
−
| 03.57
+
| 04:03
−
|Then type sum = add(5,4);
+
|Here we call the '''add function.'''
−
 
+
−
 
+
−
|-
+
−
| 04.03
+
−
|Here we call the add function.  
+
  
 
|-
 
|-
−
| 04.05
+
| 04:05
 
|Then we pass the parameters as 5 and 4.  
 
|Then we pass the parameters as 5 and 4.  
  
 
|-
 
|-
−
| 04.10
+
| 04:10
−
|5 will be stored in a and 4 will be stored in b.  
+
|5 will be stored in '''a''' and 4 will be stored in ''' b. '''
  
 
|-
 
|-
−
| 04.14
+
| 04:14
 
|The addition operation will be performed.  
 
|The addition operation will be performed.  
  
 
|-
 
|-
−
| 04.18
+
| 04:18
 
|Let us now print the result.  
 
|Let us now print the result.  
  
 
|-
 
|-
−
| 04.20
+
| 04:20
−
|Hence type here  
+
|Hence type here '''printf(“Sum is %d\n”, sum);'''
  
 
|-
 
|-
−
| 04.21
+
| 04:27
−
|printf(“Sum is %d\n”,sum);
+
−
 
+
−
|-
+
−
| 04.27
+
 
|Delete this, as we have already called the function above.  
 
|Delete this, as we have already called the function above.  
  
 
|-
 
|-
−
| 04.32
+
| 04:32
−
|Type return 0;  
+
|Type '''return 0;'''
−
 
+
  
 
|-
 
|-
−
| 04.36
+
| 04:36
−
|A non-void function must use a return statement that returns a value.  
+
|A '''non-void function''' must use a '''return''' statement that returns a value.  
−
 
+
  
 
|-
 
|-
−
| 04.41
+
| 04:41
−
|Click on Save
+
|Click on '''Save'''.
  
 
|-
 
|-
−
| 04.43
+
| 04:43
 
|Let us execute the program.  
 
|Let us execute the program.  
  
 
|-
 
|-
−
| 04.45
+
| 04:45
 
|Come back to our terminal.  
 
|Come back to our terminal.  
  
 
|-
 
|-
−
| 04.48
+
| 04:48
 
|Now compile the program as before.
 
|Now compile the program as before.
  
 
|-
 
|-
−
| 04.50
+
| 04:50
 
|Let us execute.  
 
|Let us execute.  
−
 
  
 
|-
 
|-
−
| 04.52
+
| 04:52
−
|The output is displayed as Sum is 9  
+
|The output is displayed as '''Sum is 9 '''.
−
 
+
  
 
|-
 
|-
−
| 04.57
+
| 04:57
 
|Now let us see how to execute the same program in C++.  
 
|Now let us see how to execute the same program in C++.  
  
 
|-
 
|-
−
| 05.02
+
| 05:02
 
|Come back to our program.
 
|Come back to our program.
  
 
|-
 
|-
−
| 05.04
+
| 05:04
 
|Let me change a few things here.  
 
|Let me change a few things here.  
−
 
  
 
|-
 
|-
−
| 05.07
+
| 05:07
−
|First press Shift, Ctrl and S keys simultaneously.  
+
|First press '''Shift, Ctrl and S''' keys simultaneously.  
  
 
|-
 
|-
−
| 05.12
+
| 05:12
−
|Now save the file with .cpp extension.  
+
|Now save the file with '''.cpp''' extension.  
  
 
|-
 
|-
−
| 05.18
+
| 05:18
−
|Click on Save.  
+
|Click on '''Save'''. First we will change the header file as <iostream>
  
 
|-
 
|-
−
| 05.19
+
| 05:24
−
|First we will change the header file as <iostream>
+
|We will include the '''using''' statement here.
−
 
+
  
 
|-
 
|-
−
| 05.24
+
| 05:28
−
|We will include the using statement here.  
+
|The '''function declaration''' is same in C++.  
  
 
|-
 
|-
−
| 05.28
+
| 05:32
−
|The function declaration is same in C++.
+
−
 
+
−
|-
+
−
| 05.32
+
 
|So there is no need to change anything here.  
 
|So there is no need to change anything here.  
  
 
|-
 
|-
−
| 05.37
+
| 05:37
−
|Now replace the printf statement with the  cout statement, as we use cout<< function to print a line in C++.
+
|Now replace the '''printf''' statement with the  '''cout''' statement, as we use cout<< function to print a line in C++.
  
 
|-
 
|-
−
| 05.48
+
| 05:48
−
|We don't need the format specifier and \n here.  
+
|We don't need the '''format specifier''' and '''\n''' here.  
−
 
+
  
 
|-
 
|-
−
| 05.52
+
| 05:52
−
|Delete the comma.  
+
|Delete the '''comma.'''
  
 
|-
 
|-
−
| 05.54
+
| 05:54
−
|Now, type two opening angle brackets
+
|Now, type two opening '''angle brackets'''.
  
 
|-
 
|-
−
| 05.58
+
| 05:58
−
|After sum , again type two opening angle brackets.  
+
|After sum , again type two opening '''angle brackets'''.  
  
 
|-
 
|-
−
| 06.03
+
| 06:03
−
|Within double quotes, type backslash n.  
+
|Within double quotes, type '''backslash n'''.  
  
 
|-
 
|-
−
| 06.07
+
| 06:07
 
|Delete this closing bracket.  
 
|Delete this closing bracket.  
  
 
|-
 
|-
−
| 06.09
+
| 06:09
−
|Now Click on Save.  
+
|Now Click on '''Save. '''
  
 
|-
 
|-
−
| 06.11
+
| 06:11
 
|Let us compile the program.  
 
|Let us compile the program.  
  
 
|-
 
|-
−
| 06.14
+
| 06:14
−
|Come back to the terminal.
+
|Come back to our terminal.
  
 
|-
 
|-
−
| 06.16
+
| 06:16
−
|Type g++ function dot cpp hyphen o fun1  
+
|Type '''g++ function dot cpp hyphen o fun1 '''
−
 
+
  
 
|-
 
|-
−
| 06.23
+
| 06:23
−
|Here we have fun1, this is because we don't want to overwrite the output file fun.  
+
|Here we have '''fun1''', this is because we don't want to overwrite the output file '''fun'''.  
−
 
+
  
 
|-
 
|-
−
| 06.31
+
| 06:31
−
|Press Enter.  
+
|Press '''Enter. '''
  
 
|-
 
|-
−
| 06.34
+
| 06:34
−
|Type ./fun1  
+
|Type '''./fun1 '''
−
 
+
  
 
|-
 
|-
−
| 06.38
+
| 06:38
 
|The output is displayed as: Sum is 9  
 
|The output is displayed as: Sum is 9  
  
 
|-
 
|-
−
| 06.42
+
| 06:42
 
|Now we will see the common errors which we can come across.  
 
|Now we will see the common errors which we can come across.  
  
 
|-
 
|-
−
| 06.47
+
| 06:47
 
|Suppose here, we type x in  place of 4.  
 
|Suppose here, we type x in  place of 4.  
  
 
|-
 
|-
−
| 06.51
+
| 06:51
 
|I will retain the rest of the code as it is.  
 
|I will retain the rest of the code as it is.  
  
 
|-
 
|-
−
| 06.55
+
| 06:55
−
|Click on Save.  
+
|Click on '''Save.'''
 +
 
 
|-
 
|-
−
| 06.58
+
| 06:58
 
|Let us compile the program.  
 
|Let us compile the program.  
  
 
|-
 
|-
−
| 07.02
+
| 07:02
 
|We see an error at line no. 10.  
 
|We see an error at line no. 10.  
  
 
|-
 
|-
−
| 07.06
+
| 07:06
−
|x was not declared in this scope.  
+
|''' 'x' was not declared in this scope'''.
  
 
|-
 
|-
−
| 07.09
+
| 07:09
−
|This is because x is a character variable.
+
|This is because 'x' is a '''character''' variable.
  
 
|-
 
|-
−
| 07.13
+
| 07:13
 
|It was not declared anywhere.  
 
|It was not declared anywhere.  
  
 
|-
 
|-
−
| 07.15
+
| 07:15
−
|And our add function has integer variable as an argument.  
+
|And our '''add''' function has '''integer''' variable as an '''argument'''.  
  
 
|-
 
|-
−
| 07.21
+
| 07:21
−
|So, there is a mismatch in return type and return value.  
+
|So, there is a mismatch in '''return type''' and '''return value'''.  
  
 
|-
 
|-
−
| 07.25
+
| 07:25
 
|Now come back to our program.  
 
|Now come back to our program.  
  
 
|-
 
|-
−
| 07.27
+
| 07:27
 
|Let us fix the error.  
 
|Let us fix the error.  
  
 
|-
 
|-
−
| 07.30
+
| 07:30
 
|Type 4 at line no. 10.  
 
|Type 4 at line no. 10.  
  
 
|-
 
|-
−
| 07.32
+
| 07:32
−
|Click on Save.  
+
|Click on '''Save. '''
  
 
|-
 
|-
−
| 07.35
+
| 07:35
 
|Let us execute again.  
 
|Let us execute again.  
  
 
|-
 
|-
−
| 07.37
+
| 07:37
 
|Let me clear the prompt.  
 
|Let me clear the prompt.  
  
 
|-
 
|-
−
| 07.40
+
| 07:40
 
|Compile the program as before.  
 
|Compile the program as before.  
  
 
|-
 
|-
−
| 07.42
+
| 07:42
−
|Yes! it is working.  
+
|Yes! It is working.  
  
 
|-
 
|-
−
| 07.45
+
| 07:45
 
|Now we will see another common error which we can come across.
 
|Now we will see another common error which we can come across.
  
 
|-
 
|-
−
| 07.50
+
| 07:50
 
|Suppose here we pass only one parameter.   
 
|Suppose here we pass only one parameter.   
  
 
|-
 
|-
−
| 07.55
+
| 07:55
−
|Delete 4.  
+
|Delete 4. Click on '''Save'''.
  
 
|-
 
|-
−
| 07.56
+
| 07:58
−
|Click on Save
+
−
 
+
−
|-
+
−
| 07.58
+
 
|Switch to the terminal.
 
|Switch to the terminal.
  
 
|-
 
|-
−
| 08.00
+
| 08:00
−
| Let us compile.  
+
| Let us compile.We see an error at line no 10.  
  
 
|-
 
|-
−
| 08.03
+
| 08:06
−
|We see an error at line no 10.
+
|'''too few arguments to function 'int add (int, int)' '''
  
 
|-
 
|-
−
| 08.05
+
| 08:11
−
|too few arguments to function 'int add (int, int)'
+
−
 
+
−
|-
+
−
| 08.11
+
 
|Switch back to our program.  
 
|Switch back to our program.  
−
 
  
 
|-
 
|-
−
| 08.14
+
| 08:14
 
|You can see here we have two parameters
 
|You can see here we have two parameters
  
 
|-
 
|-
−
| 08.19
+
| 08:19
−
|int a and int b.  
+
|'''int a '''and '''int b. '''
  
 
|-
 
|-
−
| 08.22
+
| 08:22
 
|And here we are passing only one parameter.  
 
|And here we are passing only one parameter.  
  
 
|-
 
|-
−
| 08.25
+
| 08:25
 
|Hence it is giving an error.  
 
|Hence it is giving an error.  
  
 
|-
 
|-
−
| 08.27
+
| 08:27
 
|Let us fix the error.  
 
|Let us fix the error.  
  
 
|-
 
|-
−
| 08.29
+
| 08:29
 
|Type 4.  
 
|Type 4.  
  
 
|-
 
|-
−
| 08.31
+
| 08:31
−
|Click on Save .  
+
|Click on '''Save''' .  
  
 
|-
 
|-
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| 08.34
+
| 08:34
 
|Switch to the terminal.  
 
|Switch to the terminal.  
  
 
|-
 
|-
−
| 08.36
+
| 08:36
 
|Let us execute again.  
 
|Let us execute again.  
  
 
|-
 
|-
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| 08.39
+
| 08:39
−
|Yes it is working!
+
|Yes! It is working.
  
 
|-
 
|-
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| 08.42
+
| 08:42
 
|Come back to our slides.  
 
|Come back to our slides.  
−
 
  
 
|-
 
|-
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| 08.44
+
| 08:44
−
|To summarise, in this tutorial we have learnt -  
+
|To summarize, in this tutorial we have learnt -  
  
 
|-
 
|-
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| 08.49
+
| 08:49
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|Function
+
|'''function''' Syntax of '''function'''
  
 
|-
 
|-
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| 08.50
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| 08:51
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|Syntax of function
+
|'''function without arguments'''
  
 
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|-
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| 08.51
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| 08:53
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|Function without arguments
+
−
 
+
−
|-
+
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| 08.53
+
 
|Eg- void add()  
 
|Eg- void add()  
  
 
|-
 
|-
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| 08.55
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| 08:55
 
|Function with arguments  
 
|Function with arguments  
  
 
|-
 
|-
−
| 08.57
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| 08:57
−
|Eg- int add(int a and  int b)  
+
|Eg- int add(int a, int b)  
  
 
|-
 
|-
−
| 09.02
+
| 09:02
−
|As an assignment-  
+
|As an assignment- Write a program to calculate the square of a number.
  
 
|-
 
|-
−
| 09.03
+
| 09:07
−
|Write a program to calculate the square of a number.  
+
|Watch the video available at the link shown below.
  
 
|-
 
|-
−
| 09.07
+
| 09:11
−
|Watch the video available at the link shown below
+
|It summarizes the Spoken Tutorial project.
  
 
|-
 
|-
−
| 09.11
+
| 09:14
−
|It summarizes the Spoken Tutorial project
+
|If you do not have good bandwidth, you can download and watch it.
  
 
|-
 
|-
−
| 09.14
+
| 09:18
−
|If you do not have good bandwidth, you can download and watch it
+
|The Spoken Tutorial Project Team:
  
 
|-
 
|-
−
| 09.18
+
| 09:21
−
|The Spoken Tutorial Project Team
+
|Conducts workshops using spoken tutorials,
  
 
|-
 
|-
−
| 09.21
+
| 09:24
−
|Conducts workshops using spoken tutorials
+
|Gives certificates to those who pass an online test.
  
 
|-
 
|-
−
| 09.24
+
| 09:28
−
|Gives certificates to those who pass an online test
+
−
 
+
−
|-
+
−
| 09.28
+
 
|For more details, please write to, contact@spoken-tutorial.org  
 
|For more details, please write to, contact@spoken-tutorial.org  
  
 
|-
 
|-
−
|09.35
+
|09:35
−
|Spoken Tutorial Project is a part of Talk to a Teacher project  
+
|Spoken Tutorial Project is a part of Talk to a Teacher project.
  
 
|-
 
|-
−
| 09.40
+
| 09:40
−
|It is supported by the National Mission on Education through ICT, MHRD, Government of India
+
|It is supported by the National Mission on Education through ICT, MHRD, Government of India.
−
 
+
  
 
|-
 
|-
−
| 09.47
+
| 09:47
−
|More information on this Mission is available at the link shown below
+
|More information on this Mission is available at the link shown below.
  
 
|-
 
|-
−
| 09.52
+
| 09:52
−
|This is Ashwini Patil from IIT Bombay  
+
|This is Ashwini Patil from IIT Bombay.
  
 
|-
 
|-
−
| 09.55
+
| 09:55
 
|Thank You for joining.
 
|Thank You for joining.

Latest revision as of 12:54, 24 March 2017

Time Narration
00:01 Welcome to the spoken tutorial on Functions in C and C++.
00:06 In this tutorial we will learn,
00:09 What is a function
00:11 Syntax of a function
00:13 Significance of return statement
00:16 We will do this through examples.
00:18 We will also see some common errors and their solutions.
00:22 To record this tutorial, I am using,
00:25 Ubuntu Operating System version 11.10,
00:29 gcc and g++ Compiler version 4.6.1 .
00:35 Let us start with the introduction to functions.
00:39 A function is a self-contained program executing a specific task.
00:45 Every program consists of one or more functions.
00:49 Once executed, the control will be returned back from where it was accessed.
00:55 Let us see the syntax for function.
00:59 ret-type defines the type of data that the function returns.
01:05 fun_name defines the name of the function.
01:09 parameters is the list of variable names and their types.
01:14 We can specify an empty parameter list.
01:18 This is called as functions without arguments.
01:21 And this is called as functions with arguments.
01:26 Let us see a program using void.
01:29 I have already typed the program on the editor.
01:32 So I will open it.
01:35 Note that our file name is function.
01:38 And I have saved the file with the extension .c (dot c).
01:43 Let me explain the code.
01:45 This is our header file.
01:47 Before using any function, it must be defined.
01:51 Here we have defined a function called add.
01:54 Note that add function is without any arguments.
01:58 And the return type is void.
02:01 There are two types of functions-
02:03 User-defined that is our add function and
02:06 Pre-defined that is printf and main function .
02:12 Here we have initialized a and b by assigning them values as 2 and 3.
02:19 Here we have declared a variable c.
02:21 Then we add the values of a and b.
02:24 The result is stored in c.
02:27 Then we print the result.
02:29 This is our main function.
02:32 Here we call the add function.
02:34 The addition operation will be performed and the result will be printed.
02:39 Now click on Save.
02:42 Let us execute the program.
02:45 Please open the terminal window by pressing Ctrl, Alt and T keys simultaneously.
02:53 To compile, type gcc function dot c hyphen o fun.
03:00 To execute, type ./fun (dot slash fun).
03:05 We see the output is displayed as Sum of a and b is 5 .
03:10 Now come back to our program.
03:13 Functions contain special identifiers called as parameters or arguments.
03:20 Let us see the same example with arguments.
03:23 I will change a few things here.
03:27 Type int add(int a, int b)
03:32 Here we have declared a function add.
03:36 int a and int b are the arguments of the function add.
03:41 Let us delete this.No need to initialize a and b here.
03:46 Delete the printf statement.
03:49 Type int main()
03:52 Let us declare a variable sum here.
03:54 Type int sum;
03:57 Then type sum = add(5,4);
04:03 Here we call the add function.
04:05 Then we pass the parameters as 5 and 4.
04:10 5 will be stored in a and 4 will be stored in b.
04:14 The addition operation will be performed.
04:18 Let us now print the result.
04:20 Hence type here printf(“Sum is %d\n”, sum);
04:27 Delete this, as we have already called the function above.
04:32 Type return 0;
04:36 A non-void function must use a return statement that returns a value.
04:41 Click on Save.
04:43 Let us execute the program.
04:45 Come back to our terminal.
04:48 Now compile the program as before.
04:50 Let us execute.
04:52 The output is displayed as Sum is 9 .
04:57 Now let us see how to execute the same program in C++.
05:02 Come back to our program.
05:04 Let me change a few things here.
05:07 First press Shift, Ctrl and S keys simultaneously.
05:12 Now save the file with .cpp extension.
05:18 Click on Save. First we will change the header file as <iostream>
05:24 We will include the using statement here.
05:28 The function declaration is same in C++.
05:32 So there is no need to change anything here.
05:37 Now replace the printf statement with the cout statement, as we use cout<< function to print a line in C++.
05:48 We don't need the format specifier and \n here.
05:52 Delete the comma.
05:54 Now, type two opening angle brackets.
05:58 After sum , again type two opening angle brackets.
06:03 Within double quotes, type backslash n.
06:07 Delete this closing bracket.
06:09 Now Click on Save.
06:11 Let us compile the program.
06:14 Come back to our terminal.
06:16 Type g++ function dot cpp hyphen o fun1
06:23 Here we have fun1, this is because we don't want to overwrite the output file fun.
06:31 Press Enter.
06:34 Type ./fun1
06:38 The output is displayed as: Sum is 9
06:42 Now we will see the common errors which we can come across.
06:47 Suppose here, we type x in place of 4.
06:51 I will retain the rest of the code as it is.
06:55 Click on Save.
06:58 Let us compile the program.
07:02 We see an error at line no. 10.
07:06 'x' was not declared in this scope.
07:09 This is because 'x' is a character variable.
07:13 It was not declared anywhere.
07:15 And our add function has integer variable as an argument.
07:21 So, there is a mismatch in return type and return value.
07:25 Now come back to our program.
07:27 Let us fix the error.
07:30 Type 4 at line no. 10.
07:32 Click on Save.
07:35 Let us execute again.
07:37 Let me clear the prompt.
07:40 Compile the program as before.
07:42 Yes! It is working.
07:45 Now we will see another common error which we can come across.
07:50 Suppose here we pass only one parameter.
07:55 Delete 4. Click on Save.
07:58 Switch to the terminal.
08:00 Let us compile.We see an error at line no 10.
08:06 too few arguments to function 'int add (int, int)'
08:11 Switch back to our program.
08:14 You can see here we have two parameters
08:19 int a and int b.
08:22 And here we are passing only one parameter.
08:25 Hence it is giving an error.
08:27 Let us fix the error.
08:29 Type 4.
08:31 Click on Save .
08:34 Switch to the terminal.
08:36 Let us execute again.
08:39 Yes! It is working.
08:42 Come back to our slides.
08:44 To summarize, in this tutorial we have learnt -
08:49 function Syntax of function
08:51 function without arguments
08:53 Eg- void add()
08:55 Function with arguments
08:57 Eg- int add(int a, int b)
09:02 As an assignment- Write a program to calculate the square of a number.
09:07 Watch the video available at the link shown below.
09:11 It summarizes the Spoken Tutorial project.
09:14 If you do not have good bandwidth, you can download and watch it.
09:18 The Spoken Tutorial Project Team:
09:21 Conducts workshops using spoken tutorials,
09:24 Gives certificates to those who pass an online test.
09:28 For more details, please write to, contact@spoken-tutorial.org
09:35 Spoken Tutorial Project is a part of Talk to a Teacher project.
09:40 It is supported by the National Mission on Education through ICT, MHRD, Government of India.
09:47 More information on this Mission is available at the link shown below.
09:52 This is Ashwini Patil from IIT Bombay.
09:55 Thank You for joining.

Contributors and Content Editors

Ashwini, Kavita salve, Krupali, PoojaMoolya, Pratik kamble, Sandhya.np14

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