模重复平方计算

#include <iostream>using namespace std;#define MAXLEN  1000void Dec_To_Bin(int Dec,int *Bin,int *len){  int i=0;  while(Dec)  {    Bin[i]=Dec%2;    Dec/=2;    i++;  }  *len=i;}int ModRepeatSquare(int b,int n,int m){  int a=1,t=b;  int len,Bin[MAXLEN];  Dec_To_Bin(n,Bin,&len);  for(int i=0;i<len;i++)  {    if(!Bin[i])    {      cout<<"n"<<i<<"="<<Bin[i]<<"\t";      a=a;      b=b*b%m;      cout<<"a"<<i<<"="<<a<<" \t"<<"b"<<i<<"="<<b<<endl;    }    else    {      cout<<"n"<<i<<"="<<Bin[i]<<"\t";      a=a*b%m;      b=b*b%m;      cout<<"a"<<i<<"="<<a<<" \t"<<"b"<<i<<"="<<b<<endl;    }  }  return a;}int main(){  int b,n,m;  cout<<"Please input b,n,m:"<<endl;  cin>>b>>n>>m;  cout<<b<<"^"<<n<<"="<<ModRepeatSquare(b,n,m)<<"(mod "<<m<<")";  return 0;}