Difference between revisions of "C-and-C++/C2/Functions/English-timed"
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| 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++''' |
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| 00.09 | | 00.09 | ||
− | |What is a function | + | |What is a '''function''' |
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| 00.11 | | 00.11 | ||
− | |Syntax of a function | + | |Syntax of a '''function''' |
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| 00.13 | | 00.13 | ||
− | |Significance of return statement | + | |Significance of '''return statement''' |
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| 00.25 | | 00.25 | ||
− | |Ubuntu Operating System version 11.10 | + | |'''Ubuntu Operating System''' version 11.10 |
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|00.29 | |00.29 | ||
− | | gcc and g++ Compiler version 4.6.1 . | + | | '''gcc''' and '''g++ Compiler''' version 4.6.1 . |
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|00.35 | |00.35 | ||
− | |Let us start with the introduction to functions | + | |Let us start with the introduction to '''functions''' |
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|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. |
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| 00.45 | | 00.45 | ||
− | |Every program consists of one or more functions. | + | |Every program consists of one or more '''functions.''' |
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| 00.55 | | 00.55 | ||
− | |Let us see the syntax for function. | + | |Let us see the syntax for '''function. ''' |
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| 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. ''' |
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| 01.05 | | 01.05 | ||
− | |fun_name defines the name of the function. | + | |'''fun_name''' defines the name of the '''function. ''' |
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|01.09 | |01.09 | ||
− | |parameters is the list of variable names and their types. | + | |'''parameters''' is the list of '''variable''' names and their types. |
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| 01.14 | | 01.14 | ||
− | |We can specify an empty parameter list. | + | |We can specify an '''empty parameter list'''. |
|- | |- | ||
| 01.18 | | 01.18 | ||
− | |This is called as functions without arguments. | + | |This is called as '''functions without arguments. ''' |
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| 01.21 | | 01.21 | ||
− | |And this is called as functions with arguments. | + | |And this is called as '''functions with arguments. ''' |
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|01.26 | |01.26 | ||
− | |Let us see a program using void. | + | |Let us see a program using '''void. ''' |
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|01.35 | |01.35 | ||
− | |Note that our filename is function. | + | |Note that our filename is '''function. ''' |
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Line 120: | Line 120: | ||
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| 01.45 | | 01.45 | ||
− | |This is our header file. | + | |This is our '''header file. ''' |
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|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.''' |
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|01.58 | |01.58 | ||
− | |And the return type is void. | + | |And the return type is '''void. ''' |
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| 02.03 | | 02.03 | ||
− | | User-defined that is our add function and | + | | '''User-defined''' that is our '''add function''' and |
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| 02.06 | | 02.06 | ||
− | | Pre-defined that is printf and main function | + | | '''Pre-defined''' that is '''printf''' and '''main function ''' |
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| 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 |
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| 02.19 | | 02.19 | ||
− | | Here we have declared a variable c. | + | | Here we have declared a variable '''c. ''' |
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| 02.29 | | 02.29 | ||
− | | This is our main function. | + | | This is our '''main function. ''' |
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| 02.32 | | 02.32 | ||
− | |Here we call the add function. | + | |Here we call the '''add function. ''' |
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| 02.39 | | 02.39 | ||
− | | Now click on Save. | + | | Now click on '''Save.''' |
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| 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. |
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| 02.53 | | 02.53 | ||
− | |To compile, type gcc function dot c hyphen o fun | + | |To compile, type '''gcc function dot c hyphen o fun''' |
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| 03.00 | | 03.00 | ||
− | |To execute, type ./fun (dot slash fun) | + | |To execute, type '''./fun''' (dot slash fun) |
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| 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 ''' |
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| 03.13 | | 03.13 | ||
− | |Functions contains special identifiers called as parameters or arguments. | + | |Functions contains special identifiers called as '''parameters''' or '''arguments.''' |
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| 03.27 | | 03.27 | ||
− | |Type int add(int a, int b) | + | |Type '''int add(int a, int b) ''' |
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| 03.32 | | 03.32 | ||
− | |Here we have declared a function add. | + | |Here we have declared a '''function add. ''' |
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| 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.''' |
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| 03.46 | | 03.46 | ||
− | |Delete the printf statement. | + | |Delete the '''printf '''statement. |
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| 03.49 | | 03.49 | ||
− | |Type int main() | + | |Type '''int main() ''' |
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| 03.52 | | 03.52 | ||
− | | Let us declare a variable sum here. | + | | Let us declare a variable '''sum''' here. |
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| 03.54 | | 03.54 | ||
− | |Type int sum; | + | |Type '''int sum; ''' |
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| 03.57 | | 03.57 | ||
− | |Then type sum = add(5,4); | + | |Then type '''sum = add(5,4); ''' |
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| 04.03 | | 04.03 | ||
− | |Here we call the add function. | + | |Here we call the '''add function.''' |
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| 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. ''' |
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| 04.21 | | 04.21 | ||
− | |printf(“Sum | + | |'''printf(“Sum is %d\n”,sum);''' |
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| 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. |
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| 04.41 | | 04.41 | ||
− | |Click on Save | + | |Click on '''Save''' |
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| 04.52 | | 04.52 | ||
− | |The output is displayed as Sum is 9 | + | |The output is displayed as '''Sum is 9 ''' |
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| 05.07 | | 05.07 | ||
− | |First press Shift, Ctrl and S keys simultaneously. | + | |First press '''Shift, Ctrl and S''' keys simultaneously. |
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| 05.12 | | 05.12 | ||
− | |Now save the file with .cpp extension. | + | |Now save the file with '''.cpp''' extension. |
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| 05.18 | | 05.18 | ||
− | |Click on Save. | + | |Click on '''Save'''. |
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| 05.24 | | 05.24 | ||
− | |We will include the using statement here. | + | |We will include the '''using''' statement here. |
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| 05.28 | | 05.28 | ||
− | |The function declaration is same in C++. | + | |The '''function declaration''' is same in C++. |
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| 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. |
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| 05.52 | | 05.52 | ||
− | |Delete the comma. | + | |Delete the '''comma.''' |
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| 05.54 | | 05.54 | ||
− | |Now, type two opening angle brackets | + | |Now, type two opening '''angle brackets''' |
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| 05.58 | | 05.58 | ||
− | |After sum , again type two opening angle brackets. | + | |After sum , again type two opening '''angle brackets'''. |
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| 06.03 | | 06.03 | ||
− | |Within double quotes, type backslash n. | + | |Within double quotes, type '''backslash n'''. |
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| 06.09 | | 06.09 | ||
− | |Now Click on Save. | + | |Now Click on '''Save. ''' |
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| 06.16 | | 06.16 | ||
− | |Type g++ function dot cpp hyphen o fun1 | + | |Type '''g++ function dot cpp hyphen o fun1 ''' |
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| 06.31 | | 06.31 | ||
− | |Press Enter. | + | |Press '''Enter. ''' |
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| 06.34 | | 06.34 | ||
− | |Type ./fun1 | + | |Type '''./fun1 ''' |
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| 06.55 | | 06.55 | ||
− | |Click on Save. | + | |Click on '''Save.''' |
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| 06.58 | | 06.58 | ||
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| 07.06 | | 07.06 | ||
− | |x was not declared in this scope. | + | |'''x was not declared in this scope. ''' |
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| 07.09 | | 07.09 | ||
− | |This is because x is a character variable. | + | |This is because '''x''' is a '''character''' variable. |
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| 07.15 | | 07.15 | ||
− | |And our add function has integer variable as an argument. | + | |And our '''add''' function has '''integer''' variable as an '''argument'''. |
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| 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'''. |
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| 07.32 | | 07.32 | ||
− | |Click on Save. | + | |Click on '''Save. ''' |
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| 07.56 | | 07.56 | ||
− | |Click on Save | + | |Click on '''Save''' |
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| 08.06 | | 08.06 | ||
− | |too few arguments to function 'int add (int, int)' | + | |'''too few arguments to function 'int add (int, int)' ''' |
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| 08.19 | | 08.19 | ||
− | |int a and int b. | + | |'''int a '''and '''int b. ''' |
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| 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. ''' |
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Line 610: | Line 610: | ||
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| 08.49 | | 08.49 | ||
− | |Function | + | |'''Function''' |
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| 08.50 | | 08.50 | ||
− | |Syntax of function | + | |Syntax of '''function''' |
|- | |- | ||
| 08.51 | | 08.51 | ||
− | |Function without arguments | + | |'''Function without arguments''' |
|- | |- |
Revision as of 12:52, 26 March 2014
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 filename is function. |
01.38 | And I have saved the file with the extentsion .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 contains 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. |
03.42 | 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 |
04.21 | 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. |
05.19 | 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. |
07.56 | Click on Save |
07.58 | Switch to the terminal. |
08.00 | Let us compile. |
08.01 | 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 summarise, in this tutorial we have learnt - |
08.49 | Function |
08.50 | 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 and int b) |
09.02 | As an assignment- |
09.03 | 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