strstr() function in C Language

• strstr( ) function returns pointer to the first occurrence of the string in a given string. Syntax for strstr( ) function is given below.

char *strstr(const char *str1, const char *str2);

Example program for strstr() function in C Language:

• In this program, strstr( ) function is used to locate first occurrence of the string “test” in the string ”This is a test string for testing”. Pointer is returned at first occurrence of the string “test”.

C

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

#include <stdio.h> #include <string.h> int main () {   char string[55] ="This is a test string for testing";   char *p;   p = strstr (string,"test");   if(p)   {     printf("string found\n" );     printf ("First occurrence of string \"test\" in \"%s\" is"\            " \"%s\"",string, p);   }   else printf("string not found\n" );    return 0; }

Output:

string found First occurrence of string “test” in “This is a test string for testing” is “test string for testing”

Other String functions C Language:

• String.h header file supports all the string functions in C language. All the string functions are given below.

S.no	String functions	Description
1	strcat ( )	Concatenates str2 at the end of str1.
2	strncat ( )	appends a portion of string to another
3	strcpy ( )	Copies str2 into str1
4	strncpy ( )	copies given number of characters of one string to another
5	strlen ( )	gives the length of str1.
6	strcmp ( )	Returns 0 if str1 is same as str2. Returns <0 if strl < str2. Returns >0 if str1 > str2.
7	strcmpi ( )	Same as strcmp() function. But, this function negotiates case.  “A” and “a” are treated as same.
8	strchr ( )	Returns pointer to first occurrence of char in str1.
9	strrchr ( )	last occurrence of given character in a string is found
10	strstr ( )	Returns pointer to first occurrence of str2 in str1.
11	strrstr ( )	Returns pointer to last occurrence of str2 in str1.
12	strdup ( )	duplicates the string
13	strlwr ( )	converts string to lowercase
14	strupr ( )	converts string to uppercase
15	strrev ( )	reverses the given string
16	strset ( )	sets all character in a string to given character
17	strnset ( )	It sets the portion of characters in a string to given character
18	strtok ( )	tokenizing given string using delimiter

www.cinterviews.com appreciates your contribution please mail us the questions you have to cinterviews.blogspot.com@gmail.com so that it will be useful to our job search community