Difference between revisions of "C-and-C++/C3/Strings/English-timed"
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| − | |Time | + | |'''Narration''' |
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| − | |Narration | + | |
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| − | | | + | |What is a '''string. ''' |
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| 00:10 | | 00:10 | ||
| − | | | + | |Declaration of a '''string. ''' |
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| 00:13 | | 00:13 | ||
| − | | | + | |Initialization of a '''string. ''' |
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| 00:15 | | 00:15 | ||
| − | | | + | |Few examples on '''string'''. |
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| 00:44 | | 00:44 | ||
| − | |Size of '''string '''= length of '''string + 1. | + | |Size of '''string '''= length of '''string''' + 1. |
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| 00:55 | | 00:55 | ||
| − | |'''char''' name of '''string''' and '''size'''. | + | |'''char''', name of '''string''' and '''size'''. |
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|01:58 | |01:58 | ||
| − | |To read a '''string''', we can use '''scanf() | + | |To read a '''string''', we can use '''scanf()''' function with format specifier '''%s'''. |
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| 02:43 | | 02:43 | ||
| − | | | + | |Now press '''Enter'''. |
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| 02:49 | | 02:49 | ||
| − | | I will type | + | | I will type "Talk To A Teacher". |
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| 03:13 | | 03:13 | ||
| − | |The syntax for this is | + | |The syntax for this is, |
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| 03:20 | | 03:20 | ||
| − | |Eg: Here we have declared a '''character string “names” | + | |Eg: Here we have declared a '''character string “names”''' with size '''10''' and the '''string''' is “Priya”" |
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| 03:28 | | 03:28 | ||
| − | |Another syntax is | + | |Another syntax is, |
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| 03:31 | | 03:31 | ||
| − | |'''char var_name[ ] = {'S', 't', 'r', 'i', 'n', 'g'}''' within single quotes | + | |'''char var_name[ ] = {'S', 't', 'r', 'i', 'n', 'g'}''' within single quotes. |
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| 03:36 | | 03:36 | ||
| − | |eg: '''char names[10] = {'P', 'r', 'i', 'y', 'a'}''' in single quotes | + | |eg: '''char names[10] = {'P', 'r', 'i', 'y', 'a'}''' in single quotes. |
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| 03:58 | | 03:58 | ||
| − | |Now save the file with the name '''stringinitialize''' | + | |Now save the file with the name '''stringinitialize'''. |
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| 04:30 | | 04:30 | ||
| − | |Let us execute. | + | |Let us execute. Come back to our '''terminal.''' |
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| 05:18 | | 05:18 | ||
| − | |Let us execute. | + | |Let us execute.Come back to our '''terminal'''. |
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| 05:23 | | 05:23 | ||
| − | |We see | + | |We see an fatal error. |
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| 05:25 | | 05:25 | ||
| − | |'''sting.h: | + | |'''sting.h: No such file or directory ''' |
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| 05:28 | | 05:28 | ||
| − | |'''compilation terminated ''' | + | |'''compilation terminated. ''' |
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| 05:45 | | 05:45 | ||
| − | |Now click on '''Save. ''' | + | |Now click on '''Save. '''Let us execute again. |
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| 06:06 | | 06:06 | ||
| − | |Now, click on Save . | + | |Now, click on Save .Let us see what happens. |
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| 06:24 | | 06:24 | ||
| − | |format %s expects argument of type 'char' but argument 2 has type 'int'. | + | |'''format %s expects argument of type 'char' but argument 2 has type 'int' '''. |
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| 07:25 | | 07:25 | ||
| − | |Now save the file with an extension '''.cpp'''(dot cpp). | + | |Now save the file with an extension '''.cpp''' (dot cpp). |
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| 08:11 | | 08:11 | ||
| − | |Delete the '''scanf''' statement and type '''getline opening bracket closing bracket within the brackets type(cin, strname) '''. | + | |Delete the '''scanf''' statement and type '''getline opening bracket closing bracket''', within the brackets type '''(cin, strname) '''. |
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| 08:40 | | 08:40 | ||
| − | |Now delete the '''comma''' | + | |Now delete the '''comma'''. |
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| 08:58 | | 08:58 | ||
| − | |Here we have declared a '''string variable 'strname' ''' | + | |Here we have declared a '''string variable 'strname' '''. |
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| 09:27 | | 09:27 | ||
|Let me clear the prompt. | |Let me clear the prompt. | ||
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| 09:30 | | 09:30 | ||
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| 09:46 | | 09:46 | ||
| − | |Press '''Enter. ''' | + | |Press '''Enter. '''It is displayed as '''Enter the string'''. |
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| 10:07 | | 10:07 | ||
| − | |Now come back to our slides. | + | |Now come back to our slides. Let us summarize. |
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| 10:11 | | 10:11 | ||
| − | |In this tutorial we learnt: | + | |In this tutorial we learnt: '''Strings ''' |
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| 10:14 | | 10:14 | ||
| − | | | + | |Declaration of a '''string ''' |
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|10:20 | |10:20 | ||
| − | | | + | |Initialization of a '''string '''eg: '''char strname[30] = “Talk To A Teacher”''' |
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| − | |More information on this | + | |More information on this mission is available at the link shown below. |
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Latest revision as of 12:43, 6 September 2017
| Time | Narration |
| 00:01 | Welcome to the spoken-tutorial on Strings in C and C++. |
| 00:06 | In this tutorial we will learn: |
| 00:08 | What is a string. |
| 00:10 | Declaration of a string. |
| 00:13 | Initialization of a string. |
| 00:15 | Few examples on string. |
| 00:17 | 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 11.04, |
| 00:29 | gcc and g++ Compiler version 4.6.1 . |
| 00:35 | Let us start with the introduction to strings. |
| 00:38 | String is a sequence of characters that is treated as a single data item. |
| 00:44 | Size of string = length of string + 1. |
| 00:49 | Let me tell you how to declare a string. |
| 00:52 | The syntax for this is |
| 00:55 | char, name of string and size. |
| 00:59 | char is the data type, name of the string is the string name, and we can give the size here. |
| 01:06 | Eg: here we have declared a character string names with size 10. |
| 01:13 | Now we will see an example. |
| 01:15 | I have already typed the program, I will open it. |
| 01:19 | Note that our file name is string.c |
| 01:23 | In this program, we will take a string as an input from the user and print it. |
| 01:29 | Let me explain the code now. |
| 01:32 | These are our header files. |
| 01:34 | Here string.h includes the declarations, functions, constants of string handling utilities. |
| 01:43 | Whenever we work on string functions, we should include this header file. |
| 01:47 | This is our main() function. |
| 01:49 | Here we are declaring the string strname with size 30. |
| 01:55 | Here we are accepting a string from the user. |
| 01:58 | To read a string, we can use scanf() function with format specifier %s. |
| 02:05 | We are using the caret sign and \n to include the spaces with the string. |
| 02:11 | Then we print the string. |
| 02:13 | And this is our return statement. |
| 02:16 | Now click on Save. |
| 02:18 | Let us execute the program. |
| 02:20 | Please open the terminal window by pressing Ctrl, Alt and T keys simultaneously on your keyboard. |
| 02:30 | To compile, type gcc space string.c space -o space str |
| 02:37 | And press Enter . |
| 02:40 | To execute, type ./str (dot slash str). |
| 02:43 | Now press Enter. |
| 02:46 | Here it is displayed as Enter the string . |
| 02:49 | I will type "Talk To A Teacher". |
| 02:56 | Now press Enter. |
| 02:58 | The output is displayed as The string is Talk To A Teacher. |
| 03:03 | Now let us switch back to our slides. |
| 03:06 | Until now we discussed about the declaration of a string. |
| 03:10 | Now we are going to discuss how to initialize the string. |
| 03:13 | The syntax for this is, |
| 03:16 | char var_name[size] = “string”; |
| 03:20 | Eg: Here we have declared a character string “names” with size 10 and the string is “Priya”" |
| 03:28 | Another syntax is, |
| 03:31 | char var_name[ ] = {'S', 't', 'r', 'i', 'n', 'g'} within single quotes. |
| 03:36 | eg: char names[10] = {'P', 'r', 'i', 'y', 'a'} in single quotes. |
| 03:42 | Let me show you how to use the first syntax with an example. |
| 03:48 | Switch back to our Editor. We will use the same example. |
| 03:52 | First, press shift, ctrl and s keys simultaneously on your keyboard. |
| 03:58 | Now save the file with the name stringinitialize. |
| 04:03 | Now click on Save. |
| 04:06 | We are going to initialize the string. |
| 04:08 | Hence, at the 5th line, type |
| 04:11 | = and within the double quotes “Spoken-Tutorial”; |
| 04:20 | Now, click on Save . |
| 04:22 | Now remove these two lines, as we are only going to print the string. |
| 04:27 | Click on Save. |
| 04:30 | Let us execute. Come back to our terminal. |
| 04:33 | To compile, type |
| 04:35 | gcc space stringinitialize.c space -o space str2 |
| 04:44 | Here we have str2 because we don't want to overwrite the output parameter str for the file string.c. |
| 04:54 | Now press Enter. |
| 04:56 | To execute, type ./str2 |
| 05:00 | The output is displayed as "The string is Spoken-Tutorial". |
| 05:06 | Now we will see some common errors which we can come across . |
| 05:09 | Come back to our program. |
| 05:11 | Suppose, here we type the spelling of string as sting. |
| 05:16 | Now click on Save. |
| 05:18 | Let us execute.Come back to our terminal. |
| 05:21 | Now compile as before. |
| 05:23 | We see an fatal error. |
| 05:25 | sting.h: No such file or directory |
| 05:28 | compilation terminated. |
| 05:30 | Come back to our program. |
| 05:32 | This is because the compiler is not able to find the header file with the name sting.h . |
| 05:39 | Hence it is giving an error. |
| 05:41 | Let us fix the error. |
| 05:43 | Type r here. |
| 05:45 | Now click on Save. Let us execute again. |
| 05:47 | Come back to our terminal. |
| 05:50 | Compile as before, execute as before. |
| 05:54 | Yes, it is working! |
| 05:56 | Now, let us see another common error. |
| 05:59 | Come back to our program. |
| 06:02 | Suppose, here I will type int in place of char. |
| 06:06 | Now, click on Save .Let us see what happens. |
| 06:09 | Come back to our terminal. |
| 06:11 | Let me clear the prompt. |
| 06:15 | Compile as before. |
| 06:17 | We see an error. |
| 06:19 | Wide character array initialized from non-wide string . |
| 06:24 | format %s expects argument of type 'char' but argument 2 has type 'int' . |
| 06:32 | Come back to our program. |
| 06:36 | This is because we used %s as the format specifier for string. |
| 06:42 | And we are initializing it with an integer data type. |
| 06:47 | Let us fix the error. |
| 06:49 | Type char here. |
| 06:51 | Click on Save. |
| 06:53 | Let us execute. Come back to our terminal. |
| 06:56 | Compile as before, execute as before. |
| 07:00 | Yes, it is working! |
| 07:03 | Now we will see how to execute the same program in C++. |
| 07:08 | Come back to our program. |
| 07:11 | Let me open our file string.c. |
| 07:15 | We will edit the code here. |
| 07:18 | First, press shift, ctrl and S keys simultaneously on your keyboard. |
| 07:25 | Now save the file with an extension .cpp (dot cpp). |
| 07:29 | and click on Save. |
| 07:33 | Now we will change the header file as iostream. |
| 07:38 | Include the using statement. |
| 07:43 | Now click on Save. |
| 07:47 | Now we will delete this declaration. |
| 07:50 | And will declare a string variable. |
| 07:53 | Type string space strname and a semicolon. |
| 07:59 | Click on Save. |
| 08:02 | Replace the printf statement with the cout statement. |
| 08:07 | Delete the closing bracket here. |
| 08:11 | Delete the scanf statement and type getline opening bracket closing bracket, within the brackets type (cin, strname) . |
| 08:24 | At the end, type a semicolon. |
| 08:28 | Now again, replace the printf statement with the cout statement. |
| 08:36 | Delete the format specifier and \n . |
| 08:40 | Now delete the comma. |
| 08:42 | Type two opening angle brackets, delete the bracket here. |
| 08:49 | Type two opening angle brackets and within the double quotes type \n . |
| 08:54 | And click on Save. |
| 08:58 | Here we have declared a string variable 'strname' . |
| 09:03 | Since we do not use the format specifier in C++, the compiler should know that 'strname' is a string variable. |
| 09:13 | Here we use getline to extract the characters from the input sequence. |
| 09:18 | It stores them as a string. |
| 09:22 | Now let us execute the program. Come back to our terminal. |
| 09:27 | Let me clear the prompt. |
| 09:30 | To compile, type |
| 09:32 | g++ space string.cpp space -o space str3 |
| 09:39 | and press Enter. |
| 09:41 | To execute, type ./str3 (dot slash str3). |
| 09:46 | Press Enter. It is displayed as Enter the string. |
| 09:50 | I will enter as Talk To A Teacher . |
| 09:55 | Now press Enter. |
| 09:57 | The output is displayed as |
| 09:59 | "The string is Talk To A Teacher" |
| 10:03 | We can see that the output is similar to our C code. |
| 10:07 | Now come back to our slides. Let us summarize. |
| 10:11 | In this tutorial we learnt: Strings |
| 10:14 | Declaration of a string |
| 10:16 | eg: char strname[30] |
| 10:20 | Initialization of a string eg: char strname[30] = “Talk To A Teacher” |
| 10:26 | As an assignment, |
| 10:28 | write a program to print a string using the 2nd syntax. |
| 10:34 | Watch the video available at the link shown below. |
| 10:37 | It summarizes the Spoken Tutorial project. |
| 10:40 | If you do not have good bandwidth, you can download and watch it. |
| 10:44 | The Spoken Tutorial Project Team: |
| 10:46 | Conducts workshops using spoken tutorials. |
| 10:49 | Gives certificates to those who pass an online test. |
| 10:54 | For more details, please write to, contact@spoken-tutorial.org. |
| 11:01 | Spoken Tutorial Project is a part of Talk to a Teacher project. |
| 11:04 | It is supported by the National Mission on Education through ICT, MHRD, Government of India. |
| 11:12 | More information on this mission is available at the link shown below. |
| 11:16 | This is Ashwini Patil from IIT Bombay, signing off. |
| 11:20 | Thank You for watching. |