Difference between revisions of "C-and-C++/C2/If-And-Else-If-statement/English-timed"

From Script | Spoken-Tutorial
Jump to: navigation, search
Line 5: Line 5:
 
|-
 
|-
 
|  00:02
 
|  00:02
|  Welcome to the spoken tutorial on '''Conditional statements in C and C++'''
+
|  Welcome to the spoken tutorial on '''Conditional statements in C and C++'''.
  
 
|-
 
|-
Line 13: Line 13:
 
|-
 
|-
 
|  00:11
 
|  00:11
| how to execute a single '''statement'''.
+
| *How to execute a single '''statement'''
  
 
|-
 
|-
 
|  00:14
 
|  00:14
| How to execute group of '''statements'''.
+
| *How to execute group of '''statements'''.
  
 
|-
 
|-
Line 33: Line 33:
 
|-
 
|-
 
|  00:31
 
|  00:31
| '''gcc''' and '''g++ Compiler''' version 4.6.1  
+
| '''gcc''' and '''g++ Compiler''' version 4.6.1.
  
 
|-
 
|-
 
| 00:38
 
| 00:38
| Let us start with the Introduction to condition '''statements'''.  
+
| Let us start with the introduction to condition '''statements'''.  
  
 
|-
 
|-
Line 45: Line 45:
 
|-
 
|-
 
|  00:49
 
|  00:49
| It helps to make decision on, what code is to be executed.
+
| It helps to make decision on what code is to be executed.
  
 
|-
 
|-
Line 57: Line 57:
 
|-
 
|-
 
| 01:07
 
| 01:07
|  Let us understand the flow of if statements.
+
|  Let us understand the flow of '''if''' statements.
  
 
|-
 
|-
 
|  01:13
 
|  01:13
| Here, if the condition is true then , '''statement1''' will be executed.
+
| Here, if the condition is true then '''statement1''' will be executed.
  
 
|-
 
|-
Line 69: Line 69:
 
|-
 
|-
 
|  01:29
 
|  01:29
|   Now we will see the flow of else if '''statement''',
+
| Now we will see the flow of '''else if''' statement.
  
 
|-
 
|-
 
|  01:32
 
|  01:32
| Here, if '''condition1''' is true then '''statement1''' will be executed.
+
| Here, if '''condition 1''' is true then '''statement 1''' will be executed.
  
 
|-
 
|-
 
|  01:41
 
|  01:41
| If '''condition1''' is false then it will check for another condition that is '''condition2'''.
+
| If '''condition 1''' is false then it will check for another condition that is '''condition 2'''.
  
 
|-
 
|-
Line 85: Line 85:
 
|-
 
|-
 
|  01:54
 
|  01:54
| And If '''condition2''' is false, then '''statement2''' will be executed
+
| And If '''condition 2''' is false, then '''statement2''' will be executed.
  
 
|-
 
|-
Line 97: Line 97:
 
|-
 
|-
 
|  02:09  
 
|  02:09  
| So let me open it.
+
| So, let me open it.
  
 
|-
 
|-
 
|  02:13
 
|  02:13
| Note that our filename is '''ifstmt.c'''
+
| Note that our file name is '''ifstmt.c'''.
  
 
|-
 
|-
Line 117: Line 117:
 
|-
 
|-
 
|  02:34
 
|  02:34
|  This is our '''main function.'''
+
|  This is our '''main()''' function.
  
 
|-
 
|-
 
| 02:38  
 
| 02:38  
|  Here we have declared three integer '''variables''' '''a, b and sum.'''
+
|  Here we have declared three '''integer variables''', '''a, b and sum.'''
  
 
|-
 
|-
 
|  02:46
 
|  02:46
|   Here we are asking for user input.
+
| Here we are asking for user input.
  
 
|-
 
|-
Line 145: Line 145:
 
|-
 
|-
 
|  03:06
 
|  03:06
| The''' format specifier '''in the''' scanf() '''helps to know the type of data.
+
| The '''format specifier''' in the '''scanf()''' helps to know the type of data.
  
 
|-
 
|-
 
|  03:10
 
|  03:10
| Like here we have %d it denotes that we are dealing with integer data type.
+
| Like here, we have '''%d''', it denotes that we are dealing with integer data type.
  
 
|-
 
|-
 
|  03:18
 
|  03:18
|  Here we add the values of''' a''' and '''b.'''
+
|  Here we add the values of '''a''' and '''b.'''
  
 
|-
 
|-
Line 165: Line 165:
 
|-
 
|-
 
|  03:29
 
|  03:29
|  This is our '''if statement.'''  
+
|  This is our '''if''' statement.
  
 
|-
 
|-
Line 177: Line 177:
 
|-
 
|-
 
|  03:42
 
|  03:42
|  Now let me comment out these lines.
+
|  Now let me comment out these lines.
  
 
|-
 
|-
 
|03:48
 
|03:48
|This is our return statement.
+
|This is our '''return''' statement.
  
 
|-
 
|-
 
|  03:51
 
|  03:51
| Now click on '''Save'''  
+
| Now click on '''Save'''.
  
 
|-
 
|-
 
|  03:53
 
|  03:53
|First we will see the execution of if statement.
+
|First we will see the execution of '''if''' statement.
  
 
|-
 
|-
 
|  03:58
 
|  03:58
|   Please open the terminal window by pressing,'''Ctrl, Alt and T''' keys simultaneously on your keyboard.
+
| Please open the terminal window by pressing,'''Ctrl, Alt''' and '''T''' keys simultaneously on your keyboard.
  
 
|-
 
|-
 
|04:09
 
|04:09
| To compile   type, '''gcc space ifstmt dot c space  -o space if'''and press enter
+
| To compile, type '''gcc space ifstmt dot c space  -o space if''' and press Enter.
  
 
|-
 
|-
 
| 04:20
 
| 04:20
|   To execute  type, '''./if''' press enter
+
| To execute, type '''./if''' (dot slash if). Press Enter.
  
 
|-
 
|-

Revision as of 18:16, 3 February 2015

Time Narration
00:02 Welcome to the spoken tutorial on Conditional statements in C and C++.
00:08 In this tutorial we will learn,
00:11 *How to execute a single statement
00:14 *How to execute group of statements.
00:16 We will do this through examples.
00:19 We will also see some common errors and their solutions.
00:25 To record this tutorial, I am using, Ubuntu Operating system version 11.10.
00:31 gcc and g++ Compiler version 4.6.1.
00:38 Let us start with the introduction to condition statements.
00:43 A statement in a program controls the flow of program execution.
00:49 It helps to make decision on what code is to be executed.
00:55 We can check the conditions, whether true or false.
01:00 We can execute a single statement or a group of statements.
01:07 Let us understand the flow of if statements.
01:13 Here, if the condition is true then statement1 will be executed.
01:20 If the condition is false then statement2 will be executed.
01:29 Now we will see the flow of else if statement.
01:32 Here, if condition 1 is true then statement 1 will be executed.
01:41 If condition 1 is false then it will check for another condition that is condition 2.
01:49 If condition2 is true, then statement3 will be executed.
01:54 And If condition 2 is false, then statement2 will be executed.
02:02 Now Let us move on to our program.
02:06 I have already typed the code on the editor.
02:09 So, let me open it.
02:13 Note that our file name is ifstmt.c.
02:18 In this program we will calculate the sum of two numbers and will check a few conditions.
02:26 Let me explain the code now.
02:30 This is our header file.
02:34 This is our main() function.
02:38 Here we have declared three integer variables, a, b and sum.
02:46 Here we are asking for user input.
02:49 User will enter the values of a and b.
02:52 The values will be stored in variable a and variable b.
02:58 The scanf() function reads data from the console.
03:02 It then stores the result in the given variable.
03:06 The format specifier in the scanf() helps to know the type of data.
03:10 Like here, we have %d, it denotes that we are dealing with integer data type.
03:18 Here we add the values of a and b.
03:22 We will store the result in sum.
03:25 Then we print the result.
03:29 This is our if statement.
03:30 Here, we check the condition whether sum is greater than 20.
03:36 If the condition is true, then we print Sum is greater than 20.
03:42 Now let me comment out these lines.
03:48 This is our return statement.
03:51 Now click on Save.
03:53 First we will see the execution of if statement.
03:58 Please open the terminal window by pressing,Ctrl, Alt and T keys simultaneously on your keyboard.
04:09 To compile, type gcc space ifstmt dot c space -o space if and press Enter.
04:20 To execute, type ./if (dot slash if). Press Enter.
04:26 it is displayed as,
04:27 Enter the value of a and b.
04:31 I will give the values as 10 and 12.
04:38 The output is displayed as Sum of a and b is 22. Sum is greater than 20.
04:45 Now come back to our program.
04:48 We will check another condition.
04:52 Let me remove the comment from here.
04:56 I will give the comment here.
05:00 Now click on Save.
05:03 This is our else-if statement.
05:05 Here, we check another condition whether Sum is greater than 10
05:11 If the condition is true then we print Sum is greater than 10 and less than 20.
05:18 Now come back to our terminal.
05:20 Let us compile as before.
05:23 Let us execute as before.
05:26 It is displayed as,
05:28 Enter the value of a and b.
05:30 I will give the values as 10 and 2.
05:35 The output is displayed as: Sum of a and b is 12.
05:38 Sum is greater than 10 and less than 20.
05:42 Let me clear the prompt.
05:44 Now come back to our program.
05:48 I will remove the comment from here and here. Now click on save,
05:56 If both the above conditions are false, then we print Sum is less than 10.
06:04 This is our else statement.
06:07 Now let us execute and see. come back to our terminal.
06:11 Let us compile as before. Let us execute as before.
06:18 Here it is displayed as,
06:19 Enter the value of a and b.
06:22 I will give the values as 3 and 5.
06:27 the output is as, sum of a and b is 8.
06:31 Sum is less than 10.
06:34 Now we will see some common errors which we can come across.
06:38 Come back to our program.
06:41 Suppose, here at the end of if statement I will type a semicolon.
06:47 Let see what will happen. Click on Save.
06:50 Let us execute. Come back to our terminal.
06:53 Let us compile as before.
06:56 We see an error: else without a previous if
07:02 Come back to our program.It is an syntax error.
07:07 If statement will never terminate with a semicolon.
07:10 And the else if statement will never work without an if.
07:16 Let us fix the error. Delete the semicolon ; here
07:22 Now Click on Save.
07:25 Let us execute. Come back to the terminal.
07:29 Let us compile as before. Let us execute as before.
07:35 Enter the value of a and b
07:37 I will give the values as 3 and 6.
07:43 The output is displayed as
07:45 Sum of a and b is 9. Sum is less than 10.
07:52 NOW WE WILL SEE HOW TO EXECUTE THE SAME PROGRAM IN C++.
07:57 Come back to our program.
07:59 I will change a few things here.
08:03 Press Shift, Ctrl and S keys simultaneously on your keyboard.
08:11 Now save the file with an extension dot cpp and click on Save
08:20 We will change the header file as, iostream
08:26 Let us include the using statement here.
08:30 Now click on the search for and replace text option .
08:35 Let us replace the printf statement with the cout statement.
08:40 Click on Replace all and click on Close
08:46 Now delete the closing brackets here.
08:49 Replace the scanf statement with the cin statement.
08:54 Type cin and two closing angle brackets >>
09:00 As we use cin >> function to read a line in C++.


09:05 Now delete the format specifiers.
09:09 Delete the comma and ampersand &
09:12 Delete the comma here and type two closing angle brackets.
09:17 Again delete the ampersandand the closing brackets. Now Click on Save.
09:25 Here delete the closing bracket and the comma.
09:31 Now delete the 'backslash n' and 'format specifier

'

09:37 Now Type two opening brackets
09:42 Again type two opening angle brackets and within the double quotes type backslash n “\n”.
09:49 Here also we will delete the closing bracket.
09:53 Now again delete the closing bracket here and here.
09:59 Now Click on Save
10:02 Let us execute.
10:04 Come back to the terminal .Let me clear the prompt.
10:10 To compile type g++ space ifstmt.cpp space -o space if1
10:20 Here we have if1 because we don't want to overwrite the output parameter if for the file ifstmt.c
10:31 Now Press Enter
10:32 To execute type ./if1 and Press Enter
10:39 Enter the value of a and b. I will give the values as 20 and 10.
10:48 The output is displayed as, Sum of a and b is 30.
10:52 Sum is greater than 20.
10:56 This brings us to the end of this tutorial.
10:59 Now come back to our slides.
11:02 Let us summarize.
11:04 In this tutorial we learned, if statement eg. if(condition)


11:11 And else if statement eg. else if(condition)
11:17 As an assignment,
11:18 Write a program to check a is greater than b or less than b.
11:24 Hint: use if statement.
11:28 Write another program to check which value is greater a, b or c.
11:34 Hint: use else-if statement.
11:38 Watch the video available at the link shown below.
11:41 It summarizes the Spoken Tutorial project.
11:44 If you do not have good bandwidth, you can download and watch it.
11:48 The Spoken Tutorial Project Team,
11:50 Conducts workshops using spoken tutorials.
11:54 Gives certificates to those who pass an online test.
11:57 For more details, please write to, contact @ spoken hyphen tutorial dot org.
12:04 Spoken Tutorial Project is a part of the Talk to a Teacher project.
12:09 It is supported by the National Mission on Education through ICT, MHRD, Government of India.
12:15 More information on this Mission is available at the link shown below.
12:20 This is Ashwini Patil from IIT BombayA

Thank You for watching.