Header File 

string.h  

Category 

C++ Prototyped Routines, Memory and String Manipulation Routines 

Prototype 

char *strstr(const char *s1, const char *s2); /* C only */ 

const char *strstr(const char *s1, const char *s2); // C++ only 

char *strstr(char *s1, const char *s2); // C++ only 

wchar_t * wcsstr(const wchar_t *s1, const wchar_t *s2); 

unsigned char * _mbsstr(const unsigned char *s1, const unsigned char *s2); 

Description 

Scans a string for the occurrence of a given substring. 

strstr scans s1 for the first occurrence of the substring s2. 

Return Value 

strstr returns a pointer to the element in s1, where s2 begins (points to s2 in s1). If s2 does not occur in s1, strstr returns null. 

Example  

#include <stdio.h>
#include <string.h>
int main(void)
{
   char *str1 = "CodeGear", *str2 = "nation", *ptr;
   ptr = strstr(str1, str2);
   printf("The substring is: %s\n", ptr);
   return 0;
}

Portability