Difference between revisions of "C-and-C++/C2/If-And-Else-If-statement/English-timed"
From Script | Spoken-Tutorial
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− | | 01. | + | | 01.32 |
| Here, if '''condition1''' is true then '''statement1''' will be executed. | | Here, if '''condition1''' is true then '''statement1''' will be executed. | ||
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− | | 02. | + | | 02.47 |
| Here we are asking for user input. | | Here we are asking for user input. | ||
|- | |- | ||
− | | 02. | + | | 02.49 |
| User will enter the values of a and b. | | User will enter the values of a and b. | ||
|- | |- | ||
− | | 02. | + | | 02.52 |
| The values will be stored in '''variable a''' and '''variable b.''' | | The values will be stored in '''variable a''' and '''variable b.''' | ||
|- | |- | ||
− | | | + | | 02.58 |
− | | 'scanf()''' reads data from the '''console.''' | + | |The 'scanf()''' reads data from the '''console.''' |
|- | |- | ||
− | | 03. | + | | 03.02 |
| It then stores the result in the given '''variable.''' | | It then stores the result in the given '''variable.''' | ||
|- | |- | ||
− | | 03. | + | | 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. | + | | 03.11 |
| 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. | + | | 03.19 |
| Here we add the values of''' a''' and '''b.''' | | Here we add the values of''' a''' and '''b.''' | ||
|- | |- | ||
− | | 03. | + | | 03.22 |
| We will store the result in '''sum.''' | | We will store the result in '''sum.''' | ||
|- | |- | ||
− | | 03. | + | | 03.26 |
| Then we print the result. | | Then we print the result. | ||
|- | |- | ||
− | | 03. | + | | 03.29 |
| This is our '''if statement.''' | | This is our '''if statement.''' | ||
|- | |- | ||
− | | 03. | + | | 03.31 |
|Here, we check the condition whether '''sum''' is greater than 20. | |Here, we check the condition whether '''sum''' is greater than 20. | ||
|- | |- | ||
− | | 03. | + | | 03.36 |
|If the condition is true, then we print '''Sum''' is greater than 20. | |If the condition is true, then we print '''Sum''' is greater than 20. | ||
|- | |- | ||
− | | 03. | + | | 03.43 |
| Now let me comment out these lines. | | Now let me comment out these lines. | ||
|- | |- | ||
− | | | + | |03.48 |
|This is our return statement. | |This is our return statement. | ||
|- | |- | ||
− | | | + | | 03.51 |
| Now click on '''Save''' | | Now click on '''Save''' | ||
|- | |- | ||
− | | | + | | 03.53 |
|First we will see the execution of if statement. | |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. | | Please open the terminal window by pressing,'''Ctrl, Alt and T''' keys simultaneously on your keyboard. | ||
|- | |- | ||
− | |04. | + | |04.09 |
| To compile type, '''gcc ifstmt.c -o if'''and press enter | | To compile type, '''gcc ifstmt.c -o if'''and press enter | ||
|- | |- | ||
− | | 04. | + | | 04.20 |
| To execute type, '''./if''' press enter | | To execute type, '''./if''' press enter | ||
|- | |- | ||
− | | 04. | + | | 04.26 |
| it is displayed as, | | it is displayed as, | ||
|- | |- | ||
− | | 04. | + | | 04.27 |
|Enter the value of a and b. | |Enter the value of a and b. | ||
|- | |- | ||
− | | 04. | + | | 04.32 |
|I will give the values as 10 and 12. | |I will give the values as 10 and 12. | ||
|- | |- | ||
− | | 04. | + | | 04.38 |
|The output is displayed as Sum of a and b is 22. Sum is greater than 20. | |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. | | Now come back to our program. | ||
|- | |- | ||
− | | | + | | 04.49 |
| We will check another condition. | | We will check another condition. | ||
|- | |- | ||
− | | | + | | 04.53 |
|Let me remove the comment from here. | |Let me remove the comment from here. | ||
|- | |- | ||
− | | | + | | 04.57 |
|I will give the comment here. | |I will give the comment here. | ||
|- | |- | ||
− | | 05. | + | | 05.00 |
|Now click on '''Save.''' | |Now click on '''Save.''' | ||
|- | |- | ||
− | | 05. | + | | 05.03 |
| This is our else-if statement. | | This is our else-if statement. | ||
|- | |- | ||
− | | 05. | + | | 05.05 |
|Here, we check another condition whether '''Sum''' is greater than 10 | |Here, we check another condition whether '''Sum''' is greater than 10 | ||
|- | |- | ||
− | | 05. | + | | 05.11 |
|If the condition is true. Then we print '''Sum''' is greater than 10 and less than 20. | |If the condition is true. Then we print '''Sum''' is greater than 10 and less than 20. | ||
|- | |- | ||
− | | 05. | + | | 05.18 |
| Now come back to our terminal. | | Now come back to our terminal. | ||
|- | |- | ||
− | | 05. | + | | 05.20 |
|Let us compile as before. Let us execute as before. | |Let us compile as before. Let us execute as before. | ||
|- | |- | ||
− | | | + | | 05.27 |
| It is displayed as, | | It is displayed as, | ||
|- | |- | ||
− | | | + | | 05.28 |
|Enter the value of a and b. | |Enter the value of a and b. | ||
|- | |- | ||
− | | | + | | 05.30 |
| I will give the values as 10 and 2. | | I will give the values as 10 and 2. | ||
|- | |- | ||
− | | | + | | 05.35 |
|The output is displayed as: Sum of a and b is 12. | |The output is displayed as: Sum of a and b is 12. | ||
|- | |- | ||
− | | | + | | 05.39 |
|Sum is greater than 10 and less than 20. | |Sum is greater than 10 and less than 20. | ||
|- | |- | ||
− | | | + | | 05.43 |
|Let me clear the prompt. Now come back to our program. | |Let me clear the prompt. Now come back to our program. | ||
|- | |- | ||
− | | | + | | 05.48 |
| I will remove the comment from here and here.Now click on save, | | I will remove the comment from here and here.Now click on save, | ||
|- | |- | ||
− | | | + | | 05.56 |
| If both the conditions are false, then we print Sum is less than 10. | | If both the conditions are false, then we print Sum is less than 10. | ||
|- | |- | ||
− | | 06. | + | | 06.04 |
|This is our else statement. | |This is our else statement. | ||
|- | |- | ||
− | | 06. | + | | 06.08 |
| Now let us execute and see. come back to our terminal. | | Now let us execute and see. come back to our terminal. | ||
|- | |- | ||
− | | 06. | + | | 06.12 |
|Let us compile as before. Let us execute as before. | |Let us compile as before. Let us execute as before. | ||
|- | |- | ||
− | | | + | | 06.18 |
| | Here it is displayed as, | | | Here it is displayed as, | ||
|- | |- | ||
− | | | + | | 06.19 |
|Enter the value of a and b. | |Enter the value of a and b. | ||
|- | |- | ||
− | | | + | | 06.22 |
|I will give the values as 3 and 5. | |I will give the values as 3 and 5. | ||
|- | |- | ||
− | | | + | | 06.27 |
| the output is as, sum of a and b is 8. | | the output is as, sum of a and b is 8. | ||
|- | |- | ||
− | | | + | | 06.31 |
|Sum is less than 10. | |Sum is less than 10. | ||
|- | |- | ||
− | | | + | | 06.34 |
| Now we will see some common errors which we can come across. | | Now we will see some common errors which we can come across. | ||
|- | |- | ||
− | | | + | | 06.38 |
|Come back to our program. | |Come back to our program. | ||
|- | |- | ||
− | | | + | | 06.41 |
| Suppose, here at the end of if statement I will type a semicolon. | | Suppose, here at the end of if statement I will type a semicolon. | ||
|- | |- | ||
− | | | + | | 06.47 |
|Let see what will happen.Click on '''Save.''' | |Let see what will happen.Click on '''Save.''' | ||
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|- | |- | ||
− | | | + | | 06.50 |
| Let us execute. Come back to our terminal. | | Let us execute. Come back to our terminal. | ||
|- | |- | ||
− | | | + | | 06.53 |
|Let us compile as before. | |Let us compile as before. | ||
|- | |- | ||
− | | | + | | 06.56 |
| We see an error: else without a previous if | | We see an error: else without a previous if | ||
|- | |- | ||
− | | 07. | + | | 07.02 |
| Come back to our program.It is an syntax error. | | Come back to our program.It is an syntax error. | ||
|- | |- | ||
− | | 07. | + | | 07.07 |
|If statement will never terminate with a semicolon. | |If statement will never terminate with a semicolon. | ||
|- | |- | ||
− | | | + | | 07.10 |
|And the else if statement will never work without an if. | |And the else if statement will never work without an if. | ||
|- | |- | ||
− | | | + | | 07.16 |
− | | Let us fix the error. Delete the | + | | Let us fix the error. Delete the semicolon ; here |
|- | |- | ||
− | | | + | | 07.22 |
| Now Click on '''Save.''' | | Now Click on '''Save.''' | ||
|- | |- | ||
− | | | + | | 07.25 |
| Let us execute. Come back to the terminal. | | Let us execute. Come back to the terminal. | ||
|- | |- | ||
− | | | + | | 07.29 |
| Let us compile as before. Let us execute as before. | | Let us compile as before. Let us execute as before. | ||
|- | |- | ||
− | | | + | | 07.35 |
|Enter the value of a and b | |Enter the value of a and b | ||
|- | |- | ||
− | | | + | | 07.37 |
|I will give the values as 3 and 6. | |I will give the values as 3 and 6. | ||
|- | |- | ||
− | | | + | | 07.44 |
|The output is displayed as | |The output is displayed as | ||
|- | |- | ||
− | | | + | | 07.46 |
|Sum of a and b is 9. Sum is less than 10. | |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++. | | | NOW WE WILL SEE HOW TO EXECUTE THE SAME PROGRAM IN C++. | ||
|- | |- | ||
− | | | + | | 07.57 |
|Come back to our program. | |Come back to our program. | ||
|- | |- | ||
− | | 08. | + | | 08.00 |
| I will change a few things here. | | I will change a few things here. | ||
|- | |- | ||
− | | | + | | 08.03 |
| Press '''Shift, Ctrl and S''' keys simultaneously on your keyboard.''' | | Press '''Shift, Ctrl and S''' keys simultaneously on your keyboard.''' | ||
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|- | |- | ||
| 08.50 | | 08.50 | ||
− | |Replace the '''scanf''' statement with the cin statement. | + | |Replace the '''scanf''' statement with the '''cin''' statement. |
|- | |- | ||
− | | 08. | + | | 08.54 |
|Type '''cin and two closing angle brackets >>''' | |Type '''cin and two closing angle brackets >>''' | ||
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|- | |- | ||
| 09.09 | | 09.09 | ||
− | |Delete the comma and & | + | |Delete the '''comma''' and '''ampersand''' &''' |
|- | |- | ||
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|- | |- | ||
| 09.17 | | 09.17 | ||
− | |Again delete the ampersand and the closing brackets Now Click on Save | + | |Again delete the '''ampersand'''and the closing brackets. Now Click on '''Save'''. |
|- | |- | ||
− | | | + | | 09.25 |
| Here delete the closing bracket and the comma. | | Here delete the closing bracket and the comma. | ||
|- | |- | ||
| 09.32 | | 09.32 | ||
− | |Now delete the backslash n and format specifier | + | |Now delete the ''''backslash n'''' and ''''format specifier''' |
− | + | ' | |
|- | |- | ||
| 09.37 | | 09.37 | ||
Line 509: | Line 509: | ||
|- | |- | ||
| 09.42 | | 09.42 | ||
− | |Again type two opening brackets ''' within double quotes backslash n “\n”.''' | + | |Again type two opening angle brackets and''' within the double quotes type backslash n “\n”.''' |
|- | |- | ||
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|- | |- | ||
| 10.10 | | 10.10 | ||
− | |To compile type g++ space ifstmt.cpp space -o space if1 | + | |To compile type '''g++ space ifstmt.cpp space -o space if1''' |
|- | |- | ||
| 10.21 | | 10.21 | ||
− | |Here we have if1 because we don't want to overwrite the output parameter for the file ifstmt.c | + | |Here we have '''if1''' because we don't want to overwrite the output parameter '''if '''for the file ifstmt.c |
|- | |- | ||
Line 549: | Line 549: | ||
|- | |- | ||
| 10.39 | | 10.39 | ||
− | |Enter the value of a and b. I will give the values as 20 and 10. | + | |Enter the value of''' a''' and '''b'''. I will give the values as 20 and 10. |
|- | |- | ||
| 10.48 | | 10.48 | ||
− | |The output is displayed as, Sum of a and b is 30. | + | |The output is displayed as, Sum of a and b is '''30'''. |
|- | |- | ||
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|- | |- | ||
− | | 10. | + | | 10.56 |
|This brings us to the end of this tutorial. | |This brings us to the end of this tutorial. | ||
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|- | |- | ||
| 11.12 | | 11.12 | ||
− | |else if statement eg. else if(condition) | + | | And else if statement eg. else if(condition) |
{…......... | {…......... | ||
Line 650: | Line 650: | ||
| This is Ashwini Patil from IIT Bombay | | This is Ashwini Patil from IIT Bombay | ||
− | Thank You for | + | Thank You for watching. |
− | + | ||
|} | |} |
Revision as of 12:15, 16 August 2013
Time' | 'Narration |
00.02 | Welcome to the spoken tutorial on Conditional statements in C and C++ |
00.09 | In this tutorial we will learn,
|
00.11 | how to execute a single statement.
|
00.14 | How to execute group of statements.
|
00.17 | We will do this through examples.
|
00.20 | 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.
|
00.32 | 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.
|
00.50 | It helps to make decision on, what code is to be executed.
|
00.56 | We can check the conditions, whether true or false.
|
01.01 | We can execute a single statement or a group of statements. |
01.08 | 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 condition1 is true then statement1 will be executed.
|
01.41 | If condition1 is false then it will check for another condition that is condition2.
|
01.50 | If condition2 is true, then statement3 will be executed.
|
01.55 | And If condition2 is false, then statement2 will be executed |
02.03 | 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 filename is ifstmt.c |
02.19 | In this program we will calculate the sum of two numbers and will check a few conditions. |
02.27 | Let me explain the code now.
|
02.31 | 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. |
02.47 | 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() 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.
|
03.11 | Like here we have %d it denotes that we are dealing with integer data type. |
03.19 | Here we add the values of a and b.
|
03.22 | We will store the result in sum. |
03.26 | Then we print the result. |
03.29 | This is our if statement. |
03.31 | 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. |
03.43 | 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 ifstmt.c -o ifand press enter |
04.20 | To execute type, ./if press enter |
04.26 | it is displayed as, |
04.27 | Enter the value of a and b. |
04.32 | 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. |
04.49 | We will check another condition. |
04.53 | Let me remove the comment from here. |
04.57 | 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. Let us execute as before. |
05.27 | 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. |
05.39 | Sum is greater than 10 and less than 20. |
05.43 | Let me clear the prompt. 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 conditions are false, then we print Sum is less than 10. |
06.04 | This is our else statement. |
06.08 | Now let us execute and see. come back to our terminal. |
06.12 | 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. |
07.44 | The output is displayed as |
07.46 | 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. |
08.00 | 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 .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 . |
08.36 | let us replace printf statement with cout statement. |
08.40 | Click on Replace all and click on Close
|
08.46 | Now delete the closing brackets here. |
08.50 | 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++.
|
09.06 | 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. |
09.32 | 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. |
09.54 | Now again delete the closing bracket here and here. |
09.59 | Now Click on Save |
10.03 | 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 |
10.21 | 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 |
10.33 | 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. |
10.53 | Sum is greater than 20. |
10.56 | This brings us to the end of this tutorial. |
10.59 | Now come back to our slides. |
11.03 | Let us summarize. |
11.04 | In this tutorial we learned, if statement eg. if(condition)
{…........ } |
11.12 | And else if statement eg. else if(condition)
{…......... } |
11.18 | As an assignment, |
11.19 | 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. |
11.39 | Watch the video available at the link shown below. http://spoken-tutorial.org /What\_is\_a\_Spoken\_Tutorial |
11.41 | It summarizes the Spoken Tutorial project. |
11.44 | If you do not have good bandwidth, you can download and watch it. |
11.49 | The Spoken Tutorial Project Team, |
11.51 | Conducts workshops using spoken tutorials. |
11.54 | Gives certificates to those who pass an online test. |
11.58 | For more details, please write to, contact [at] spoken hyphen tutorial dot org. |
12.05 | 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. |
12.16 | More information on this Mission is available at the link shown below. (http://spoken-tutorial.org\NMEICT-Intro) |
12.21 | This is Ashwini Patil from IIT Bombay
Thank You for watching. |
Contributors and Content Editors
Ashwini, Devraj, Kavita salve, Krupali, PoojaMoolya, Priyacst, Sakinashaikh, Sandhya.np14, Sneha