C-and-C++/C3/String-Library-Functions/English-timed
From Script | Spoken-Tutorial
| Time | Narration |
| 00:01 | Welcome to the spoken-tutorial on String Library Functions in C. |
| 00:07 | In this tutorial we will learn |
| 00:09 | String Library Functions. |
| 00:11 | We will do this with the help of some examples. |
| 00:15 | To record this tutorial, I am using |
| 00:18 | Ubuntu Operating System version 11.10, |
| 00:22 | gcc Compiler Version 4.6.1. |
| 00:27 | Let us start with an introduction to string library functions. |
| 00:31 | These are the group of functions implementing operations on strings. |
| 00:36 | Various operations such as copying, concatenation, searching etc are supported. |
| 00:44 | Let us see some of the string library functions. |
| 00:48 | Here we have the strncpy function. |
| 00:52 | The syntax for this is strncpy(char str1, char str2, and int n ); |
| 01:02 | It copies first n characters of string str2 into string str1. |
| 01:09 | example, char strncpy( char hello, char world, 2); |
| 01:16 | The output will be Wollo . |
| 01:21 | Here we have Wo from the string 2 and rest of the characters from string 1. |
| 01:29 | Now we will see strncmp function, the syntax for this is strncmp(char str1, char str2, and int n); |
| 01:42 | It will compare first n characters of string 2 with string 1. |
| 01:48 | example int strncmp(char ice, char icecream, and 2); |
| 01:55 | The output will be 0. |
| 01:58 | Now we will see how to use the string library functions. |
| 02:02 | I am going to show you some of the commonly used string functions. |
| 02:07 | I have already typed the program on the editor, |
| 02:10 | I will open it. |
| 02:12 | Here, we have the string length function. |
| 02:15 | Note that our file name is strlen.c. |
| 02:20 | In this, we will find the length of the string. |
| 02:23 | These are the header files as stdio.h and string.h. |
| 02:29 | This is our main() function. |
| 02:31 | Here we have a character variable 'arr'. |
| 02:35 | It stores a value 'Ashwini' . |
| 02:38 | Then we have an integer variable len1 . |
| 02:42 | Here we will find the length of the string using strlen function. |
| 02:48 | The result will be stored in 'len1'. |
| 02:52 | Then we print the string and the length of the string. |
| 02:56 | And this is our return statement. |
| 02:59 | Now let us execute the program. |
| 03:01 | Open the terminal window by pressing |
| 03:04 | Ctrl, Alt and T keys simultaneously on your keyboard. |
| 03:09 | To compile, type: "gcc" space "strlen.c" space “-o” space “str1”. Press Enter. |
| 03:19 | Type (dot slash) ./str1. Press Enter. |
| 03:24 | The output is displayed as |
| 03:26 | string = Ashwini, Length = 7 |
| 03:30 | You can count here. 1,2,3,4,5,6, and 7. |
| 03:37 | Let us see another string function. |
| 03:40 | Here we have the string copy function. |
| 03:43 | Note that our file name is strcpy.c . |
| 03:48 | In this, we will copy the source string into the target string. |
| 03:53 | Here we have 'Ice' in the source string, it will be copied to the target string. |
| 03:59 | This is our strcpy function |
| 04:02 | Here we will print the source string and the target string. |
| 04:07 | Let us execute and see. |
| 04:09 | Come back to our terminal. |
| 04:11 | To compile, type gcc space strcpy.c space hyphen o space str2. Press Enter |
| 04:20 | Type (dot slash)./str2 . Press Enter . |
| 04:24 | The output is displayed as: |
| 04:26 | source string = Ice |
| 04:29 | target string = Ice |
| 04:32 | Now let us see another string function. |
| 04:34 | Now we will see the string compare function. |
| 04:37 | Note that our file name is strcmp.c. |
| 04:42 | In this, we will compare two strings. |
| 04:46 | Here we have character variables as str1 and str2 . |
| 04:52 | str1 stores the value as 'Ice' and str2 stores the value as 'Cream'. |
| 04:58 | Here we have integer variables as i and j. |
| 05:03 | In this we will compare the string using the strcmp function. |
| 05:08 | Here we compare str1 i.e 'Ice' with 'Hello'. |
| 05:14 | The result is stored in i. |
| 05:16 | In this we will compare string2 i.e 'Cream' with 'Cream' |
| 05:23 | The result is stored in j. |
| 05:25 | Then we print both the results. |
| 05:28 | And this is our return statement. |
| 05:31 | Let us execute the program. |
| 05:33 | Come back to our terminal. |
| 05:35 | To compile type gcc space strcmp.c space hyphen o space str3 |
| 05:46 | Press Enter. |
| 05:47 | Type (dot slash) ./str3 |
| 05:50 | The output is displayed as 1, 0. |
| 05:54 | Come back to our program. |
| 05:56 | Here we get 1 and here we get as 0. |
| 06:01 | Let us come back to our slides. |
| 06:04 | Let us summarize. |
| 06:06 | In this tutorial we learned,String library functions- |
| 06:09 | strlen() |
| 06:11 | strcpy() |
| 06:13 | strcmp() strncpy() |
| 06:16 | and strncmp(). |
| 06:19 | As an assignemnt, |
| 06:21 | write a C Program to concatenate String 'best' and String 'bus'. |
| 06:25 | Hint: strcat(char str1, char str2); |
| 06:32 | Also explore the other functions in string library. |
| 06:36 | Watch the video available at the link shown below. |
| 06:39 | It summarizes the Spoken Tutorial project. |
| 06:42 | If you do not have good bandwidth, you can download and watch it. |
| 06:46 | The Spoken Tutorial Project Team: |
| 06:49 | Conducts workshops using spoken tutorials. |
| 06:52 | Gives certificates to those who pass an online test. |
| 06:56 | For more details, please write to, contact@spoken-tutorial.org. |
| 07:03 | Spoken Tutorial Project is a part of the Talk to a Teacher project. |
| 07:08 | It is supported by the National Mission on Education through ICT, MHRD, Government of India. |
| 07:15 | More information on this mission is available at the link shown below. |
| 07:20 | This is Ashwini Patil from IIT Bombay, signing off. |
| 07:24 | Thank you for joining. |
