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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.

Contributors and Content Editors

Krupali, PoojaMoolya, Pratik kamble, Sandhya.np14, Sneha