OK呀好吧，这道题也是十分的简单

#include <iostream>
using namespace std;
string s;
int n,x;
char c;
int main()
{
	cin>>n;
	while(n!=0){
		x=n%2;
		c=x+'0';
		s=c+s;
		n=n/2;
	}
	if(s==""){
		cout<<0;
	}else{
		cout<<s;
	}
	return 0;