大指数幂模运算.cpp

本程序的功能是实现大指数幂的模运算

#include <iostream>
using namespace std;

#define PUBLICKEY 187

long module(long key,long exponential)	//key:底数	exponential:指数	mod:模
{
	if (exponential==0)		return 1;
	long mod=module(key,exponential/2);
	if (exponential%2==0)	return mod*mod%PUBLICKEY;
	else return (mod*mod)%PUBLICKEY*key%PUBLICKEY; 
}

main()
{
	long key,exponential;
	cout<<"			大指数幂模运算"<<endl;
	cout<<"请输入底数:";
	cin>>key;
	cout<<"请输入指数:";
	cin>>exponential;
	cout<<"模为: "<<module(key,exponential)<<endl;
	return 0;
}