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. |
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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. |