#include <iostream>
#include <math.h>
#include <iomanip>

using namespace std;

int main(int argc, char const *argv[])
{

    long number;
    double sqrts[256];

    int k = 0;
    while ( cin >> number )
    {
        sqrts[k] = sqrt(number);
        k++;
    }

    for ( int n = k - 1; n > -1; n-- ) {
        cout << fixed << setprecision(4) << sqrts[n] << endl;
    }

    return 0;
}

Edited by author 29.11.2018 20:32

http://acm.timus.ru/help.aspx?topic=cpp

C and C++ programs are compiled on the server with the 32-bit Microsoft Visual C++ 2017 or MinGW GCC 7.1 or Clang 4.0.1.

So sizeof(long)==4. You should run locally/debug programs using 32 bit compiler too.

Btw, why do you think 256 sqrts is enough? How did you estimate it?