#include <stdio.h>

int strstr_custom(const char *haystack, const char *needle) {
    int index = 0;
    const char *n = needle;
    
    while (*haystack) {
        const char *h = haystack;//imp Reset the pointers to the current position in the string

        while (*n && (*h == *n)) {//*h++ or h++ both same
            *h++;
            n++;
        }

        if (*n == '\0') {
            return index;
        }
        *haystack++;
        index++;
    }
    return -1;
}

int main() {
    const char *haystack = "Hello, World!";
    const char *needle = "World";

    int result = strstr_custom(haystack, needle);

    printf("Substring found at position: %d\n", result);

    return 0;
}

#if 0

#include <stdio.h>

int strsstr(char a[], char f[]){
    int c = 0;
    
    for(int i=0;a[i]!='\0';i++){
        char *b = a;
        while((*b==*f) && *f){//imp
            *b++;
            *f++;
        }
        if(*f=='\0'){
            return c;
        }
        *a++;
        c++;
    }
    return -1;
}

int main() {
    char a[30] = "my name is adarsh";
    char f[10] = "name";

    int len = strsstr(a,f);
    printf("%d",len);
}

#endif