Rabin-Karp string matching algorithm

rabin_karp.c

#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

#define INVALID_OP -1
#define NOT_FOUND -2

typedef enum {TRUE = 0, FALSE} boolean;

int rabin_karp(char *P, size_t m, char *T, size_t n, int d) {
    int p = 0, t = 0;
    int h = (int)pow(d, m-1) % d;
    for (int i = 0; i < n-m+1; i++) {
        p = (d * p + P[i]-'0') % d;
        t = (d * t + T[i]-'0') % d;
    }
    for (int s = 0; s < n-m+1; s++) {
        printf("%d\n", t);
        if (p == t) {
            if (strncmp(P, T+s, m) == 0)
                printf("Patterns occurs wth shift %d\n", s);
        }
        if (s < n - m)
            t = (d * (t - (T[s+1] - '0')*h) + T[s+m+1] - '0') % d;
    }
    return 0;
}

int main(int argc, char **argv) {
    rabin_karp(argv[1], strlen(argv[1]), argv[2], strlen(argv[2]), 10);
    return 0;
}