Segregate 0s and 1s in an array

#include<bits/stdc++.h>
using namespace std;

int main() {
	
	int t,n,i,c0;
	cin >> t;
	while(t--)
	{
	    c0=0;
	    cin >> n;
	    int ar[n];
	    for(i=0;i<n;i++)
	    cin >> ar[i];
	    for(i=0;i<n;i++)
	    if(ar[i]==0)
	    c0++;
	    for(i=0;i<c0;i++)
	    ar[i]=0;
	    for(i=c0;i<n;i++)
	    ar[i]=1;
	    for(i=0;i<n;i++)
	    cout << ar[i] << " ";
	    cout << endl;
	    
	}
	return 0;
}