random - sumy

#include<iostream>
#include<ctime>
#include<cstdlib>
#include<windows.h>
using namespace std;

int main()
{
    int x, y, z, sum=0, a;
    srand(time(NULL));
    x= rand()%27+1;
    y= rand()%27+1;
    z= rand()%27+1;
    sum = x+y+z;

    cout << "System wylosowal 3 cyfry z przedzialu 1-28, oto one: " << endl;
    cout << "x wynosi: " << x << endl;
    cout << "y wynosi: " << y << endl;
    cout << "z wynosi: " << z << endl;
    cout << "Ile wynosi ich suma?" << endl;

    while(a!=sum)
    {
        cout << "Suma to: ";
        cin >> a;
        if(a!=sum)
        {
            cout << "Zle! policz dokladnie!" << endl << endl;
            Sleep(1500);
        }
    }

    return 0;
}