From Script | Spoken-Tutorial
Revision as of 17:19, 16 July 2013 by Sneha (Talk | contribs)

(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search
Time' Narration
00:02 Welcome to the spoken-tutorial on String Library Functions in C
00:07 In this tutorial, we will learn,
00:10 String Library Functions
00:12 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,
00:23 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.
00:37 Various operations such as copying, concatenation, searching etc are supported.
00:45 Let us see some of the string library functions
00:49 Here we have the strncpy function
00:52 The syntax for this is strncpy(char str1, char str2, int n )
01:02 It copies first n characters of string str2 into string str1.
01:10 eg. char strncpy(char hello, char world, 2);
01:17 The output will be ;Wollo
01:21 Here we have Wo fromt the string 2 and rest of the characters from string 1
01:29 Now we will see strcmp function, the syntax for this is strncmp (char str1, char str2 and int n)
01:43 It will compare first n characters of string 2 with string 1
01:49 eg. int strncmp(char ice, char icecream, int 2);
01:56 The output will be 0
01:58 Now we will see how to use the string library functions.
02:03 I am going to show you some of the commonly used string functions.
02:08 I have already typed the program on the editor,
02:11 i will open it
02:12 Here we have the string length function
02:15 Note that our filename is strlen.c.
02:20 In this we will find the length of the string
02:24 These are the header files as stdio.h and string.h
02:29 This is our main function
02:32 Here we have a character variable 'arr',
02:36 It stores a value 'Ashwini'
02:39 Then we have an integer variable len1

02:43 here we will find the lenght of the string using strlen funtion
02:49 the result will be stored in len1
02:53 Then we print the string and the length of the string.
02:57 And this is our return statement

02:59 Now let us execute the program
03:02 Open the terminal window by pressing
03:04 Ctrl, Alt and T keys simultaneously on your keyboard
03:10 To compile
03:11 Type: "gcc" space "strlen.c" space “-o” space “str1”.
03:19 Press Enter
03:20 type: ./str1
03:23 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
03:38 Let us see another string function
03:41 Here we have the string copy fuction
03:43 Note that our filename is strcpy.c.
03:49 In this we will copy the source string into the target string
03:54 Here we have Ice in the source string, it will be copied to the target string .
04:00 This is our strcpy function
04:03 Here we 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
04:12 gcc space strcpy.c space -o space str2
04:19 Press Enter
04:21 Type ./str2
04:23 Press Enter

04:25 The output is displayed as
04:27 source string = Ice
04:30 target string = Ice
04:32 Now let us see another string function
04:35 Now we will see the string compare function
04:38 Note that our filename is strcmp.c
04:43 In this we will comapre two strings
04:47 Here we have character variables as str1 and str2


04:53 str 1 stores the value as 'Ice' and str2 stores the value as 'Cream'.
04:59 Here we have interger variables as i and j
05:04 In this we will compare the string using the strcmp function
05: 09 Here we compare str1 ie: 'Ice' with 'Hello'
05:14 The result is stored in i
05:17 In this we will compare string 2 ie: '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
05:37 gcc space strcmp.c space -o space str3
05:46 Press Enter
05:48 Type ./str3
05:51 The outpur is displayed as 1,0
05:55 Come back to our program
05:57 Here we get 1
055:59 and here we get as 0
06:02 Let us move back to our slides
06:04 Let us summarize,
06:06 In this tutorial we learned,
06:08 String library functions
06:09 strlen()
06:11 strcpy()
06:13 strcmp()
06:15 strncpy()
06:17 and strncmp()

06:20 As an assignemnt,
06:21 Write a C Program to concatenate String best and String bus.
06:25 Hint: strcat(char str1, char str2);
06:33 Also explore the other functions in string library.
06:37 Watch the video available at the link shown below http://spoken-tutorial.org /What\_is\_a\_Spoken\_Tutorial
06:40 It summarises the Spoken Tutorial project
06:43 If you do not have good bandwidth, you can download and watch it.
06:47 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 [at] spoken hyphen tutorial dot org
07:04 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
07:16 More information on this Mission is available at: http://spoken-tutorial.org\NMEICT-Intro
07:21 This is Ashwini Patil from IIT Bombay.
07:24 Thank you for joining.

Contributors and Content Editors

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