C :

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<ctype.h>
int a[10001];
int main(){
    int n,i,k=0;
    scanf("%d",&n);
    if(n==0){
    	printf("%d",0);
    	return 0;
	}
    while(n!=0){
    	k++;
    	a[k] = n%2;
    	n = n/2;
	}
	for(i=k;i>=1;i--){
		printf("%d",a[i]);
	}
    return 0;
}

C++ :

#include <iostream>
#include <cstring>
using namespace std;

int main(){
	int n,i = 0;
	char s[1000] = "";
	cin>>n;
	while(n != 0){
		s[i] = n % 2 + 48;
		i++;
		n = n / 2;
	}
	for (i = strlen(s) - 1;i >= 0;i--){
		cout<<s[i];
	}
}

Java :

import java.util.Scanner;
public class Main{
	public static void main(String[] args) {
		Scanner scanner=new Scanner(System.in);
		Integer num=scanner.nextInt();
	    System.out.println(Integer.toBinaryString(num));
	}
}

Python :

n = int( input() )
s=''
while n==0:
    print('0')
    break
while n!=0:
    s = str(n % 2) + s
    n = n // 2
print(s)