#include <iostream>
using namespace std;
int main()
{
    double a,b,c,d;
    cin >> a >> b >> c >> d;

    cout << sqrt(d) << endl
        << sqrt(c) << endl
        << sqrt(b) << endl
        << sqrt(a) << endl;

    return 0;
}

Why you read 4 numbers?

yes i also have done with 4 numbers now i am in a fix how to terminate it with undefined number set....help me...