Rabin-Karp Exact String Match

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <math.h>
#include <string>
#include <sys/time.h>

int p = 2, N = 2013889;
int hit_count = 0;

struct timeval start, end;
void timer_start()
{
gettimeofday(&start, 0);
}
void timer_end(char *what)
{
    gettimeofday(&end, 0);
    printf("%s: %ldusec\n", what, (end.tv_sec*1000000 + end.tv_usec) - (start.tv_sec*1000000 + start.tv_usec));
}


int power(int base, int exp)
{
    if(exp == 0) return 1;

    else return (int)pow(base, exp);
}

int hash(char *string)
{
    int result = 0, i = 0;
    while(string[i] != '\0')
    {
        result += (string[i]*(power(p,(strlen(string)-i-1)))) % N;
        i++;
    }

    return result % N;
}

int main()
{
    FILE *text = fopen("biblia.txt", "r");
    std::string stext;
    while(!feof(text))
    {
        char c = fgetc(text);
        stext += c;
    }

    timer_start();


    char *string = "Jerusalem";
    int string_hash = hash(string);
    char *rect = (char*)malloc(strlen(string)*sizeof(char));
    int i;
    for(i = 0; i < strlen(string); i++)rect[i] = stext[i];
    int rect_hash = hash(rect);

    if(string_hash == rect_hash)
    {
        if(strcmp(string, rect) == 0) hit_count++;
    }

    int stextlen = stext.length();
    int b = (power(p,(strlen(rect)-1) ));
    int len = strlen(string);
    for(int i = len; i < stextlen; i++)
    {
        char c = stext[i];

        rect_hash -= (rect[0]*b);
        rect_hash =  (rect_hash * p);
        rect_hash += c;
        rect_hash %= N;

        int k;
        for(k = 0; k < len-1; k++)rect[k] = rect[k+1];

        rect[len-1] = c;


        if(string_hash == rect_hash)
        {
            if(memcmp(string, rect, len) == 0) hit_count++;
        }
    }
    timer_end("rabin karp");
    printf("%d\n", hit_count);
}