#include <stdio.h> 
 #include <string.h> 
 int main () 
 { 
   char str[] ="This is a simple string"; 
   char * pch; 
   pch = strstr (str,"simple"); 
  strncpy (pch,"sample", 5); 
 puts (str); 
 
 
 
 
 getch();
  return 0; 
}