短除法

#include<stdio.h>
int main()
{
    int n;
    while(scanf("%d",&n)!=EOF){
        if(n==0){
            printf("0\n");
            continue;
        }int a[1001],num=0;
        while(n>0){
            a[num]=n%2;
            n=n/2;
            num++;
        }for(int i=num-1;i>=0;i--){
            printf("%d",a[i]);
        }printf("\n");
    }
    return 0;
}

易懂的笨方法👀️

#include <stdio.h>
int main(){
    int n;
    while(scanf("%d",&n)!=EOF){
        int a[1000]={0},i=0;
        while(n>=0){
            if(n%2==1){
                a[i]=1;
                n/=2;
                i++;
            }
            else{
                a[i]=0;
                n/=2;
                i++;
            }
            if(n==0)break;
        }i--;
         for(;i>=0;i--){
                printf("%d",a[i]);
            }
            printf("\n");
    }
}

#include <iostream>

using namespace std;

int main(){
std::ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);	
	int n;
	while(cin >> n){
	int p=0;
	if(n==0){
		cout << "0" << '\n';
		continue;
	}
	for(int i=31;i>=0;i--){
		if((n>>i&1)){           //去除无效的0 
			p=1;
		}
		if(p==1){
		cout << (n>>i&1);       //&运算输出 1&1=1 0&1=0 
	}
	}
		cout << '\n';
}
	return 0;
}