#include<stdio.h>
int strindex(char s[], chart[]) {
int i, j, k;
for (i = 0; s[i] != '\0';i++) {
for (j=i, k=0;t[k]!='\0' && s[j]==t[k]; j++, k++)
;
if (k > 0&& t[k] == '\0')
return i;
}
return -1;
}
int main(){
chars1[]="abcdefg123"; chars2[]="def";
printf(s1); printf("\n"); printf(s2); printf("\n");
int k=strindex(s1,s2);
printf("%d \n",k);
return 0;
}