strstr() Function in C: Finding Substring in String
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strstr() function returns pointer to the first occurrence of the string in a given string. Syntax for strstr( ) function is given below.
Syntax
char *strstr(const char *str1, const char *str2);
Returns
The strstr() function returns a pointer to the first occurrence in the string pointed to by str1 of the string pointed to by str2. It returns a null pointer if no match is found.
Program 1
This program displays the message is is a test:
#include#include void main(void) { char *poin; poin = strstr("this is a test", "is"); printf(poin); }
Output
is is a test
Program 2
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".
#include#include 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 "tes t string for testing"