#include <stdio.h>

#include <string.h>

#include <alloc.h>

#include <conio.h>

void timchuoi(char *source, char *substr, int *k)

{

char *stmp, *dtmp, *found;

stmp = strlwr(strdup(source)); // Ham strlwr co the thay bang ham strupr

dtmp = strlwr(strdup(substr));

found = strstr(stmp, dtmp);

if (found)

*k = found - stmp;

else

*k = -1;

free(stmp);

free(dtmp);

}

void main()

{

char source[255], substr[50];

int k;

printf("

Nhap chuoi nguon : ");

gets(source);

printf("

Nhap chuoi tim kiem : ");

gets(substr);

timchuoi(source, substr, &k);

if (k != -1)

printf("

Chuoi tim thay tai vi tri : %d", k);

else

printf("

Khong tim thay chuoi da cho");

getch();

}