Hexadecimal to Decimal (Int)

hex2int.h

#include <math.h>
#include <string.h>

int hex2int(const char * s)
{
    char charset[] = "0123456789abcdef";
    int i = (int)strlen(s), len = i, num = 0, j = 0;
    while (i >= 0) {
        for (j = 0; j < 16; j++) {
            if (charset[j] == s[i]) {
                num += j * (int)pow(16, len-i-1);
                break;
            }
        }
        i--;
    }
    return (num);
}