计算幂 51Nod 1046 A^B Mod C

#include <iostream>
#include <stdio.h>
using namespace std;
long long a,b,c;
long long mod(long long a,long long b,long long c)
{
    if(b==1) return a%c;
    long long z;
    z=((a%c)*(a%c))%c;
    if(b%2==1){
        z=(a*mod(z,b/2,c))%c;
        return z;
    }
    else  return mod(z,b/2,c);
}
int main()
{
    while(scanf("%lld%lld%lld",&a,&b,&c)!=EOF){
        printf("%lld\n",mod(a,b,c));
    }
    return 0;
}