Check if the second string is contained in the first string - C String

C examples for String:String Function

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Description

Check if the second string is contained in the first string

Demo Code

#include <stdio.h>  
#include <string.h>  

#define LEN 20  //  w  ww  .ja  va 2 s .  c  om
char * string_in(const char * s1, const char * s2);  

int main(void) {  
    char orig[LEN] = "test";  
    char * find;  
          
    puts(orig);  
    find = string_in(orig, "port");  
    if (find)  
        puts(find);  
    else  
        puts("Not found");  
    find = string_in(orig, "part");  
    if (find)  
        puts(find);  
    else  
        puts("Not found");  
      
    return 0;  
}  
  
char * string_in(const char * s1, const char * s2) {  
    int l2 = strlen(s2);  
    int tries;            /* maximum number of comparisons    */  
    int nomatch = 1;      /* set to 0 if match is found        */  
      
    tries = strlen(s1) + 1 - l2;  
    
    if (tries > 0)  
        while (( nomatch = strncmp(s1, s2, l2)) && tries--)  
            s1++;
    if (nomatch)
        return NULL;
    else  
        return (char *) s1;  /* cast const away */  
}

Result


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