// ConsoleApplication4.cpp : Defines the entry point for the console application.
//
#include <cstdlib>
#include <iostream>
#include <stdio.h>
#include <math.h>
#include <string.h>

using namespace std;


int main()
{
    int count = 0;
    int maxCount = 0;

    long long MyArray[255];

    for(int i=0; i<=255; i++){
        MyArray[i] = -1;
    }

    while (scanf("%llu", &MyArray[count]) != EOF){

        count++;
        maxCount = count;
        if (count > 255){
            break;
        }
    }


    for (int i = maxCount-1; i >= 0; i--){

        if(MyArray[i] !=   -1){
            long double result = 0;
            result = sqrt((long double)(MyArray[i]));
            printf("%.4Lf\n", result);
        }
    }

    system("PAUSE");
    return EXIT_SUCCESS;
}

system("pause") must be deleted

It does not work