Difference between revisions of "C-and-C++/C2/Increment-And-Decrement-Operators/English-timed"

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{| border=1
 
{| border=1
−
|| ''Time'''
+
|| '''Time'''
 
|| '''Narration'''
 
|| '''Narration'''
−
 
  
 
|-
 
|-
−
| 00.01
+
| 00:01
 
| Welcome to the spoken tutorial on '''Increment and Decrement Operators in C and C++'''.
 
| Welcome to the spoken tutorial on '''Increment and Decrement Operators in C and C++'''.
  
 
|-
 
|-
−
|  00.08
+
|  00:08
 
| In this tutorial, we will learn about:
 
| In this tutorial, we will learn about:
  
 
|-
 
|-
−
|  00.10
+
|  00:10
−
|Increment and decrement operators
+
|Increment and decrement operators.
  
 
|-
 
|-
−
|  00.12
+
|  00:12
−
|++ eg. a++ which is postfix increment operator.
+
| '++' eg. a++ which is postfix increment operator.
  
 
|-
 
|-
−
|  00.18
+
|  00:18
−
|++a which is prefix increment operator.
+
| ++a which is prefix increment operator.
−
 
+
  
 
|-
 
|-
−
|  00.22
+
|  00:22
−
|  - - . a- -  is  a postfix decrement operator.
+
|  '--' eg. a--  is  a postfix decrement operator.
−
 
+
  
 
|-
 
|-
−
|  00.27
+
|  00:27
−
|  - -a   is a  prefix decrement operator.
+
|  --a is a  prefix decrement operator.
  
 
|-
 
|-
−
|  00.31
+
|  00:31
−
|We will also learn about Type casting.
+
|We will also learn about Typecasting.
  
 
|-
 
|-
−
| 00.35
+
| 00:35
−
|  To record this tutorial, I am using: '''Ubuntu 11.10''' as the operating system  
+
|  To record this tutorial, I am using: '''Ubuntu 11.10''' as the operating system,
  
 
|-
 
|-
−
|  00.40
+
|  00:40
−
|'''gcc''' and '''g++ Compiler''' version''' 4.6.1 '''in''' Ubuntu'''.
+
|'''gcc''' and '''g++ Compiler''' version 4.6.1 in '''Ubuntu'''.
  
 
|-
 
|-
−
|  00.48
+
|  00:48
 
|  The '''++''' operator increases the existing value of the operand by one.
 
|  The '''++''' operator increases the existing value of the operand by one.
−
 
  
 
|-
 
|-
−
|  00.54
+
|  00:54
−
|'''a++''' and '''++a''' are equivalent to ''a = a + 1''.
+
|'''a++''' and '''++a''' are equivalent to '''a = a + 1'''.
  
 
|-
 
|-
−
| 01.00
+
| 01:00
 
|The '''--''' operator decreases the existing value of the operand by one.
 
|The '''--''' operator decreases the existing value of the operand by one.
  
 
|-
 
|-
−
|  01.06
+
|  01:06
 
|'''a--''' and '''--a''' are equivalent to '''a = a - 1'''.
 
|'''a--''' and '''--a''' are equivalent to '''a = a - 1'''.
  
 
|-
 
|-
−
| 01.13
+
| 01:13
 
|  I will now demonstrate the use of increment and decrement operators with the help of a C program.
 
|  I will now demonstrate the use of increment and decrement operators with the help of a C program.
  
 
|-
 
|-
−
|  01.19
+
|  01:19
 
|I have already made the program, so I'll explain the code.
 
|I have already made the program, so I'll explain the code.
  
 
|-
 
|-
−
|  01.25
+
|  01:25
 
|Here, we have the code for increment and decrement operators in '''C.'''
 
|Here, we have the code for increment and decrement operators in '''C.'''
  
 
|-
 
|-
−
|  01.30
+
|  01:30
 
|  Here, I have taken an integer variable '''a''' that holds the value '''1'''.
 
|  Here, I have taken an integer variable '''a''' that holds the value '''1'''.
  
 
|-
 
|-
−
|  01.35
+
|  01:35
 
|This way we will be able to observe the changes in the value of '''a'''.
 
|This way we will be able to observe the changes in the value of '''a'''.
  
 
|-
 
|-
−
|  01.39
+
|  01:39
 
|It will thus give us a better idea about the working of the operators.
 
|It will thus give us a better idea about the working of the operators.
  
 
|-
 
|-
−
|  01.47
+
|  01:47
 
|  Let's see how the '''postfix''' increment operator works.
 
|  Let's see how the '''postfix''' increment operator works.
  
 
|-
 
|-
−
| 01.51
+
| 01:51
 
|The output of this printf statement is 1.
 
|The output of this printf statement is 1.
  
 
|-
 
|-
−
|  01.55
+
|  01:55
−
|The value wont change.
+
|The value won't change.
  
 
|-
 
|-
−
| 01.57
+
| 01:57
 
|This is because the postfix operation occurs after the operand is evaluated.
 
|This is because the postfix operation occurs after the operand is evaluated.
  
 
|-
 
|-
−
|  02.04
+
|  02:04
 
|If an operation is performed on '''a++''', it is performed on the current value of '''a'''.
 
|If an operation is performed on '''a++''', it is performed on the current value of '''a'''.
  
 
|-
 
|-
−
|  02.10
+
|  02:10
 
|After that the value of '''a''' is incremented.
 
|After that the value of '''a''' is incremented.
  
 
|-
 
|-
−
| 02.17
+
| 02:17
 
|  Now if we see the value of''' a '''here, it has been incremented by 1.
 
|  Now if we see the value of''' a '''here, it has been incremented by 1.
  
 
|-
 
|-
−
| 02.27
+
| 02:27
−
|  We again initialize a to 1 so as to reflect on the changes.
+
|  We again initialize 'a' to 1 so as to reflect on the changes.
  
 
|-
 
|-
−
|  02.35
+
|  02:35
−
|  We now come to the prefix increment operators
+
|  We now come to the prefix increment operators.
  
 
|-
 
|-
−
|  02.38
+
|  02:38
 
|  This printf statement prints 2 on the screen.
 
|  This printf statement prints 2 on the screen.
  
 
|-
 
|-
−
|  02.42
+
|  02:42
 
|  This is because a prefix operation occurs before the operand is evaluated.
 
|  This is because a prefix operation occurs before the operand is evaluated.
  
 
|-
 
|-
−
|  02.49
+
|  02:49
−
|  So the value of a is first incremented by 1 and then it is printed.
+
|  So the value of 'a' is first incremented by 1 and then it is printed.
  
 
|-
 
|-
−
|  02.58
+
|  02:58
 
|  We again print a's value to see that there are no further changes.
 
|  We again print a's value to see that there are no further changes.
  
 
|-
 
|-
−
|  03.03
+
|  03:03
−
|  Now lets check by executing this code.
+
|  Now let's check by executing this code.
  
 
|-
 
|-
−
|  03.07
+
|  03:07
 
|  I will comment out the following lines. Type /*, */
 
|  I will comment out the following lines. Type /*, */
  
 
|-
 
|-
−
| 03.19   
+
| 03:19   
 
|  Click on '''Save'''.
 
|  Click on '''Save'''.
  
 
|-
 
|-
−
|  03.22
+
|  03:22
 
|  I have saved my file as '''incrdecr.c'''.
 
|  I have saved my file as '''incrdecr.c'''.
  
 
|-
 
|-
−
|  03.29
+
|  03:29
−
|  Open the terminal window by pressing '''Ctrl, Alt and T '''keys''' '''simultaneously.
+
|  Open the terminal window by pressing '''Ctrl, Alt''' and '''T '''keys simultaneously.
  
 
|-
 
|-
−
|  03.35
+
|  03:35
−
|  To compile, type the following on the terminal  '''gcc space incrdecr dot c space minus o space incr'''. Press enter.
+
|  To compile, type the following on the terminal; '''gcc space incrdecr dot c space minus o space incr'''. Press Enter.
  
 
|-
 
|-
−
|  03.51
+
|  03:51
−
|  To execute the code, type ''./incr''. Press enter.
+
|  To execute the code, type ''./incr'' (dot slash incr). Press enter.
  
 
|-
 
|-
−
|  03.59
+
|  03:59
−
|  The output is displayed on the screen,
+
|  The output is displayed on the screen.
  
 
|-
 
|-
−
|  04.01
+
|  04:01
−
|  This is the output when you print a++
+
|  This is the output when you print a++.
  
−
|-
+
|-
−
|  04.06
+
|  04:06
 
|  This is the output when you print ++a.
 
|  This is the output when you print ++a.
  
 
|-
 
|-
−
|  04.09
+
|  04:09
 
|  We  can see that the result is as discussed before.
 
|  We  can see that the result is as discussed before.
−
 
  
 
|-
 
|-
−
| 04.13
+
| 04:13
 
| Now Coming back to the rest of the program.
 
| Now Coming back to the rest of the program.
  
 
|-
 
|-
−
|  04.16
+
|  04:16
 
|  I will now explain the postfix and prefix  decrement operators.
 
|  I will now explain the postfix and prefix  decrement operators.
  
 
|-
 
|-
−
|  04.21
+
|  04:21
−
| Remove the multiline comments from here and here .
+
| Remove the multi-line comments from here and here .
  
−
 
 
|-
 
|-
−
|  04.29
+
|  04:29
 
| We now again assign the value of ''1'' to ''a''.
 
| We now again assign the value of ''1'' to ''a''.
  
 
|-
 
|-
−
|  04.35
+
|  04:35
 
|  This '''printf''' statement outputs the value of 1 as explained previously.
 
|  This '''printf''' statement outputs the value of 1 as explained previously.
  
 
|-
 
|-
−
|  04.40
+
|  04:40
−
|  A's value will be decremented after a-- is evaluated as its a postfix expression.
+
|  '''a's '''value will be decremented after '''a--''' is evaluated as it is a postfix expression.
−
 
+
  
 
|-
 
|-
−
|  04.47
+
|  04:47
 
|  The next statement prints a's value as o.
 
|  The next statement prints a's value as o.
  
 
|-
 
|-
−
|  04.51
+
|  04:51
−
| A's value has now being decremeted by 1.
+
| '''a's ''' value has now being decremented by 1.
  
 
|-
 
|-
−
|  04.54
+
|  04:54
 
|  We now have the prefix decrement operator.
 
|  We now have the prefix decrement operator.
  
 
|-
 
|-
−
|  04.58
+
|  04:58
 
|  Output of this printf statement would be 0.
 
|  Output of this printf statement would be 0.
  
 
|-
 
|-
−
|  05.00
+
|  05:00
 
|  As it is a prefix operation.
 
|  As it is a prefix operation.
  
 
|-
 
|-
−
|  05.05
+
|  05:05
 
|  The prefix operation occurs before the operand is evaluated.
 
|  The prefix operation occurs before the operand is evaluated.
  
 
|-
 
|-
−
|  05.09
+
|  05:09
 
|  This printf statements output is 0.
 
|  This printf statements output is 0.
  
 
|-
 
|-
−
|  05.11
+
|  05:11
−
|  No further changes have being made to a's value.
+
|  No further changes have been made to a's value.
  
 
|-
 
|-
−
|  05.15
+
|  05:15
−
|  Type return 0;  And close the ending curly bracket
+
|  Type '''return 0;''' and close the ending curly bracket.
  
 
|-
 
|-
−
| 05.21
+
| 05:21
 
|  Click on '''Save.'''
 
|  Click on '''Save.'''
  
 
|-
 
|-
−
|  05.24
+
|  05:24
 
|  Switch back to the terminal.
 
|  Switch back to the terminal.
  
 
|-
 
|-
−
|  05.27
+
|  05:27
−
|  To compile type the following on the terminal; gcc space incrdecr dot c space minus o space incr. Press Enter.
+
|  To compile, type the following on the terminal; '''gcc space incrdecr dot c space minus o space incr'''. Press Enter.
  
 
|-
 
|-
−
|  05.42
+
|  05:42
−
|  Execute type, ./incr.Press Enter.
+
|  To execute, type '''./incr'''. Press Enter.
  
 
|-
 
|-
−
|  05.52
+
|  05:52
−
|  This is the output when you print a--
+
|  This is the output when you print a--.
−
 
+
 
   
 
   
 
|-
 
|-
−
|  05.56
+
|  05:56
−
|  This is the output when you print --a  
+
|  This is the output when you print --a.
−
 
+
 
   
 
   
 
|-
 
|-
−
|  05.59
+
|  05:59
−
|  So, now we see how the increment and   decrement operator works.
+
|  So, now we see how the increment and decrement operator work.
  
 
|-
 
|-
−
|  06.05
+
|  06:05
−
| If we want to write the same program in C++.
+
| If we want to write the same program in C++,
  
 
|-
 
|-
−
|  06.07
+
|  06:07
 
|  I can make a few changes to the above C code.
 
|  I can make a few changes to the above C code.
  
 
|-
 
|-
−
|  06.10
+
|  06:10
 
|  Let me go back to the editor.  
 
|  Let me go back to the editor.  
  
 
|-
 
|-
−
|  06.13
+
|  06:13
 
|  Here is the '''C++ '''file with the necessary code.
 
|  Here is the '''C++ '''file with the necessary code.
−
 
  
 
|-
 
|-
−
|  06.16
+
|  06:16
−
|  Notice that the header is different from the C file header.
+
|  Notice that the '''header''' is different from the C file header.
  
 
|-
 
|-
−
|  06.20
+
|  06:20
 
|  We have the '''using namespace '''statement also.
 
|  We have the '''using namespace '''statement also.
  
 
|-
 
|-
−
|  06.24
+
|  06:24
−
|  Also, note that the output statement in C++ is ''cout''.
+
|  Also note that the output statement in C++ is '''cout'''.
  
 
|-
 
|-
−
|  06.28
+
|  06:28
 
|  So, apart from these differences, the two codes are very similar.
 
|  So, apart from these differences, the two codes are very similar.
  
 
|-
 
|-
−
|  06.33
+
|  06:33
−
|  Save the file. The file is saved with an extension ''.cpp''
+
|  Save the file. The file is saved with an extension '''.cpp'''.
  
 
|-
 
|-
−
| 06.40  
+
| 06:40  
 
|  Let's compile the code.
 
|  Let's compile the code.
  
 
|-
 
|-
−
|  06.42
+
|  06:42
 
|  Open the terminal and type  '''g++ space incrdecr dot cpp space minus o space incr'''. Press Enter.
 
|  Open the terminal and type  '''g++ space incrdecr dot cpp space minus o space incr'''. Press Enter.
  
 
|-
 
|-
−
|  07.00
+
|  07:00
−
| Execute  Type '''./ incr'''.Press Enter.
+
| To execute, type '''./ incr''' (dot slash incr). Press Enter.
  
 
|-
 
|-
−
|  07.07
+
|  07:07
−
|  The output is displayed on the screen:
+
|  The output is displayed on the screen.
−
 
+
−
 
+
 
   
 
   
 
|-
 
|-
−
|  07.10
+
|  07:10
 
|  So, we see the output is identical to the C program.
 
|  So, we see the output is identical to the C program.
  
 
|-
 
|-
−
|  07.15
+
|  07:15
 
| We now have the concept of typecasting.
 
| We now have the concept of typecasting.
  
 
|-
 
|-
−
|  07.17
+
|  07:17
−
|  It is implemented the same way in both '''C '''and '''C++'''.
+
|  It is implemented the same way in both '''C''' and '''C++'''.
  
 
|-
 
|-
−
|  07.22
+
|  07:22
−
|  Typecasting is a used to make a variable of one type, act like another type.
+
|  Typecasting is used to make a variable of one type, act like another type.
  
 
|-
 
|-
−
| 07.27
+
| 07:27
−
|  Typecasting is done by enclosing the data type you want within parenthesis.
+
|  Typecasting is done by enclosing the data type, you want, within parentheses.
  
 
|-
 
|-
−
|  07.33
+
|  07:33
 
|  This cast is put in front of the variable you want to cast.
 
|  This cast is put in front of the variable you want to cast.
  
 
|-
 
|-
−
|  07.38
+
|  07:38
 
|  This '''typecast''' is valid for one single operation only.
 
|  This '''typecast''' is valid for one single operation only.
  
 
|-
 
|-
−
|  07.42
+
|  07:42
−
|  Now '''a''' will behave as a '''float''' variable for a single operation.
+
|  Now '''a'''' will behave as a '''float''' variable, for a single operation.
  
 
|-
 
|-
−
| 07.47
+
| 07:47
 
|  Here is an example that I have already created.
 
|  Here is an example that I have already created.
  
 
|-
 
|-
−
|  07.50
+
|  07:50
 
|  I shall now explain the code.
 
|  I shall now explain the code.
  
 
|-
 
|-
−
|  07.54
+
|  07:54
−
| We first declare variables '''a''' and '''b''' as integer and '''c''' as float.
+
| We first declare variables '''a''' and '''b''' as integers and '''c''' as float.
  
 
|-
 
|-
−
|  08.00
+
|  08:00
 
|  '''a''' is assigned the value of  5. '''b''' is assigned the value of 2.
 
|  '''a''' is assigned the value of  5. '''b''' is assigned the value of 2.
  
 
|-
 
|-
−
|  08.06
+
|  08:06
 
|  We will perform operations on '''a''' and '''b'''.
 
|  We will perform operations on '''a''' and '''b'''.
  
 
|-
 
|-
−
| 08.10
+
| 08:10
 
|  We divide '''a''' by '''b'''. The result of division is stored in '''c'''.
 
|  We divide '''a''' by '''b'''. The result of division is stored in '''c'''.
  
 
|-
 
|-
−
|  08.14
+
|  08:14
 
|  We have used '''%.2f''' to denote a precision of 2 decimal places.
 
|  We have used '''%.2f''' to denote a precision of 2 decimal places.
  
 
|-
 
|-
−
|  08.20
+
|  08:20
 
|  The result displayed will be 2.00 against the expected result of 2.50.
 
|  The result displayed will be 2.00 against the expected result of 2.50.
  
 
|-
 
|-
−
|  08.25
+
|  08:25
 
|  The fractional part has been truncated as both the operands '''a''' and '''b''' are integers.
 
|  The fractional part has been truncated as both the operands '''a''' and '''b''' are integers.
  
 
|-
 
|-
−
|  08.31
+
|  08:31
−
|  To perform real division one of the operands will have to be type cast to float.
+
|  To perform real division, one of the operands will have to be typecast to float.
  
 
|-
 
|-
−
|  08.35
+
|  08:35
 
|  Here we are typecasting '''a '''to float. '''c''' now holds the value of real division.
 
|  Here we are typecasting '''a '''to float. '''c''' now holds the value of real division.
  
 
|-
 
|-
−
|  08.41
+
|  08:41
 
|  Now the result of real division is displayed. The answer is 2.50 as expected.
 
|  Now the result of real division is displayed. The answer is 2.50 as expected.
  
 
|-
 
|-
−
| 08.47
+
| 08:47
 
|  Type''' return 0;'''  and close the  ending curly bracket.
 
|  Type''' return 0;'''  and close the  ending curly bracket.
  
 
|-
 
|-
−
| 08.51
+
| 08:51
−
|  Click on '''Save'''. Save the file with '''.c''' extension.
+
|  Click on '''Save'''. Save the file with '''.c''' (dot c) extension.
  
 
|-
 
|-
−
|  08.55
+
|  08:55
 
|  I have saved my file as '''typecast.c'''.
 
|  I have saved my file as '''typecast.c'''.
  
 
|-
 
|-
−
|  08.59
+
|  08:59
 
|  Open the terminal.
 
|  Open the terminal.
  
 
|-
 
|-
−
|  09.01
+
|  09:01
−
|  To compile, type '''gcc space typecast dot c space minus o space type'''.Press Enter.
+
|  To compile, type '''gcc space typecast dot c space minus o space type'''. Press Enter.
  
 
|-
 
|-
−
|  09.17
+
|  09:17
−
|  to execute, type '''./type'''.Press Enter.  
+
|  To execute, type '''./type'''. Press Enter.  
  
 
|-
 
|-
−
|  09.25
+
|  09:25
 
| The output is displayed on the screen.
 
| The output is displayed on the screen.
−
 
 
   
 
   
 
|-
 
|-
−
|  09.27
+
|  09:27
 
| Looking at the two values we see the effects of typecasting.
 
| Looking at the two values we see the effects of typecasting.
  
 
|-
 
|-
−
|  09.32
+
|  09:32
 
|  We will summarize the tutorial now.  
 
|  We will summarize the tutorial now.  
  
 
|-
 
|-
−
|  09.34
+
|  09:34
−
|  In this tutorial we learnt,
+
|  In this tutorial we learnt-
  
 
|-
 
|-
−
|  09.36
+
|  09:36
−
|  How to  use the increment and decrement operators.
+
|  how to  use the increment and decrement operators,
  
 
|-
 
|-
−
|  09.40
+
|  09:40
−
|  We learn't about the forms, Postfix  and Prefix   
+
|  we learnt about the forms, Postfix  and Prefix,  
−
 
+
  
 
|-
 
|-
−
|  09.44
+
|  09:44
−
| Also we  learnt about typecasting and how it is used.
+
| also we  learnt about typecasting and how it is used.
  
 
|-
 
|-
−
|  09.47
+
|  09:47
 
|  As an assignment:
 
|  As an assignment:
  
 
|-
 
|-
−
|  09.49
+
|  09:49
−
|  Write a program to solve the following expression, a divided by b plus c divided by d
+
|  Write a program to solve the following expression, a divided by b plus c divided by d.
  
 
|-
 
|-
−
|  09.56
+
|  09:56
 
|  The values of '''a, b, c''' and '''d''' are taken as input from the user.
 
|  The values of '''a, b, c''' and '''d''' are taken as input from the user.
  
 
|-
 
|-
−
|  10.01
+
|  10:01
 
|  Use typecasting to perform real division.
 
|  Use typecasting to perform real division.
  
 
|-  
 
|-  
−
|  10.05
+
|  10:05
−
|  Watch the video available at the following link  
+
|  Watch the video available at the following link.
  
 
|-
 
|-
−
|  10.08
+
|  10:08
−
|  It summarises the Spoken Tutorial project  
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|  It summarizes the Spoken Tutorial project.
  
 
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|-
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| 10.10
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| 10:10
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|  If you do not have good bandwidth, you can download and watch it  
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|  If you do not have good bandwidth, you can download and watch it.
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+
  
 
|-
 
|-
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|  10.15
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|  10:15
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|  The Spoken Tutorial Project Team  
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|  The Spoken Tutorial Project Team:
  
 
|-
 
|-
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|  10.17
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|  10:17
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|   Conducts workshops using spoken tutorials  
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| Conducts workshops using spoken tutorials.
  
 
|-
 
|-
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|  10.20
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|  10:20
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|  Gives certificates for those who pass an online test  
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|  Gives certificates for those who pass an online test.
  
 
|-
 
|-
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|  10.24
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|  10:24
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|  For more details, please write to contact at spoken hyphen tutorial dot org
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|  For more details, please write to contact at spoken hyphen tutorial dot org.
  
 
|-
 
|-
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| 10.33
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| 10:33
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|Spoken Tutorial Project is a part of the Talk to a Teacher project  
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|Spoken Tutorial Project is a part of the Talk to a Teacher project.
  
 
|-
 
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|  10.37
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|  10:37
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|  It is supported by the National Mission on Education through ICT, MHRD, Government of India   
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|  It is supported by the National Mission on Education through ICT, MHRD, Government of India.  
  
 
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|  10.44
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|  10:44
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|  More information on this Mission is available at  spoken hyphen tutorial dot org slash NMEICT hyphen  Intro  
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|  More information on this mission is available at  spoken hyphen tutorial dot org slash NMEICT hyphen  Intro.
  
 
|-
 
|-
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|  10.55
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|  10:55
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|  This is Ritwik Joshi from IIT Bombay.  
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|  This is Ritwik Joshi from IIT Bombay.Thank you for joining.  
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Thank you for joining.  
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Latest revision as of 13:07, 24 March 2017

Time Narration
00:01 Welcome to the spoken tutorial on Increment and Decrement Operators in C and C++.
00:08 In this tutorial, we will learn about:
00:10 Increment and decrement operators.
00:12 '++' eg. a++ which is postfix increment operator.
00:18 ++a which is prefix increment operator.
00:22 '--' eg. a-- is a postfix decrement operator.
00:27 --a is a prefix decrement operator.
00:31 We will also learn about Typecasting.
00:35 To record this tutorial, I am using: Ubuntu 11.10 as the operating system,
00:40 gcc and g++ Compiler version 4.6.1 in Ubuntu.
00:48 The ++ operator increases the existing value of the operand by one.
00:54 a++ and ++a are equivalent to a = a + 1.
01:00 The -- operator decreases the existing value of the operand by one.
01:06 a-- and --a are equivalent to a = a - 1.
01:13 I will now demonstrate the use of increment and decrement operators with the help of a C program.
01:19 I have already made the program, so I'll explain the code.
01:25 Here, we have the code for increment and decrement operators in C.
01:30 Here, I have taken an integer variable a that holds the value 1.
01:35 This way we will be able to observe the changes in the value of a.
01:39 It will thus give us a better idea about the working of the operators.
01:47 Let's see how the postfix increment operator works.
01:51 The output of this printf statement is 1.
01:55 The value won't change.
01:57 This is because the postfix operation occurs after the operand is evaluated.
02:04 If an operation is performed on a++, it is performed on the current value of a.
02:10 After that the value of a is incremented.
02:17 Now if we see the value of a here, it has been incremented by 1.
02:27 We again initialize 'a' to 1 so as to reflect on the changes.
02:35 We now come to the prefix increment operators.
02:38 This printf statement prints 2 on the screen.
02:42 This is because a prefix operation occurs before the operand is evaluated.
02:49 So the value of 'a' is first incremented by 1 and then it is printed.
02:58 We again print a's value to see that there are no further changes.
03:03 Now let's check by executing this code.
03:07 I will comment out the following lines. Type /*, */
03:19 Click on Save.
03:22 I have saved my file as incrdecr.c.
03:29 Open the terminal window by pressing Ctrl, Alt and T keys simultaneously.
03:35 To compile, type the following on the terminal; gcc space incrdecr dot c space minus o space incr. Press Enter.
03:51 To execute the code, type ./incr (dot slash incr). Press enter.
03:59 The output is displayed on the screen.
04:01 This is the output when you print a++.
04:06 This is the output when you print ++a.
04:09 We can see that the result is as discussed before.
04:13 Now Coming back to the rest of the program.
04:16 I will now explain the postfix and prefix decrement operators.
04:21 Remove the multi-line comments from here and here .
04:29 We now again assign the value of 1 to a.
04:35 This printf statement outputs the value of 1 as explained previously.
04:40 a's value will be decremented after a-- is evaluated as it is a postfix expression.
04:47 The next statement prints a's value as o.
04:51 a's value has now being decremented by 1.
04:54 We now have the prefix decrement operator.
04:58 Output of this printf statement would be 0.
05:00 As it is a prefix operation.
05:05 The prefix operation occurs before the operand is evaluated.
05:09 This printf statements output is 0.
05:11 No further changes have been made to a's value.
05:15 Type return 0; and close the ending curly bracket.
05:21 Click on Save.
05:24 Switch back to the terminal.
05:27 To compile, type the following on the terminal; gcc space incrdecr dot c space minus o space incr. Press Enter.
05:42 To execute, type ./incr. Press Enter.
05:52 This is the output when you print a--.
05:56 This is the output when you print --a.
05:59 So, now we see how the increment and decrement operator work.
06:05 If we want to write the same program in C++,
06:07 I can make a few changes to the above C code.
06:10 Let me go back to the editor.
06:13 Here is the C++ file with the necessary code.
06:16 Notice that the header is different from the C file header.
06:20 We have the using namespace statement also.
06:24 Also note that the output statement in C++ is cout.
06:28 So, apart from these differences, the two codes are very similar.
06:33 Save the file. The file is saved with an extension .cpp.
06:40 Let's compile the code.
06:42 Open the terminal and type g++ space incrdecr dot cpp space minus o space incr. Press Enter.
07:00 To execute, type ./ incr (dot slash incr). Press Enter.
07:07 The output is displayed on the screen.
07:10 So, we see the output is identical to the C program.
07:15 We now have the concept of typecasting.
07:17 It is implemented the same way in both C and C++.
07:22 Typecasting is used to make a variable of one type, act like another type.
07:27 Typecasting is done by enclosing the data type, you want, within parentheses.
07:33 This cast is put in front of the variable you want to cast.
07:38 This typecast is valid for one single operation only.
07:42 Now a' will behave as a float variable, for a single operation.
07:47 Here is an example that I have already created.
07:50 I shall now explain the code.
07:54 We first declare variables a and b as integers and c as float.
08:00 a is assigned the value of 5. b is assigned the value of 2.
08:06 We will perform operations on a and b.
08:10 We divide a by b. The result of division is stored in c.
08:14 We have used %.2f to denote a precision of 2 decimal places.
08:20 The result displayed will be 2.00 against the expected result of 2.50.
08:25 The fractional part has been truncated as both the operands a and b are integers.
08:31 To perform real division, one of the operands will have to be typecast to float.
08:35 Here we are typecasting a to float. c now holds the value of real division.
08:41 Now the result of real division is displayed. The answer is 2.50 as expected.
08:47 Type return 0; and close the ending curly bracket.
08:51 Click on Save. Save the file with .c (dot c) extension.
08:55 I have saved my file as typecast.c.
08:59 Open the terminal.
09:01 To compile, type gcc space typecast dot c space minus o space type. Press Enter.
09:17 To execute, type ./type. Press Enter.
09:25 The output is displayed on the screen.
09:27 Looking at the two values we see the effects of typecasting.
09:32 We will summarize the tutorial now.
09:34 In this tutorial we learnt-
09:36 how to use the increment and decrement operators,
09:40 we learnt about the forms, Postfix and Prefix,
09:44 also we learnt about typecasting and how it is used.
09:47 As an assignment:
09:49 Write a program to solve the following expression, a divided by b plus c divided by d.
09:56 The values of a, b, c and d are taken as input from the user.
10:01 Use typecasting to perform real division.
10:05 Watch the video available at the following link.
10:08 It summarizes the Spoken Tutorial project.
10:10 If you do not have good bandwidth, you can download and watch it.
10:15 The Spoken Tutorial Project Team:
10:17 Conducts workshops using spoken tutorials.
10:20 Gives certificates for those who pass an online test.
10:24 For more details, please write to contact at spoken hyphen tutorial dot org.
10:33 Spoken Tutorial Project is a part of the Talk to a Teacher project.
10:37 It is supported by the National Mission on Education through ICT, MHRD, Government of India.
10:44 More information on this mission is available at spoken hyphen tutorial dot org slash NMEICT hyphen Intro.
10:55 This is Ritwik Joshi from IIT Bombay.Thank you for joining.
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