字符串 进制转换
#include<bits/stdc++.h>
using namespace std;
int main()
{
string s;
int n,x;
char c;
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;
}