#include <iostream>
#include <cmath>
#include <iomanip>
using namespace std;
int main(){
    long a;
    double b[100000];
    int i=0;
    cin>>a;
    while(a!=EOF){
    if (a>=0) {b[i]=sqrt((double)a);i++;}
    else  continue;
    cin>>a;
    }
    cout.setf(ios::fixed);
    cout.setf(ios::showpoint);
    for(int j=i-1;j>=0;j--) cout<<setprecision(4)<<b[i]<<endl;
return 0;
}

And please check your solution at least on sample test before posting on board.