If Else demonstration

// for MS C++ 2001+
// for gcc remove stdio and system

// #include "stdafx.h" // only for win32 console app wizard MSVC++

#include <iostream>
#include <stdio.h>
#include <math.h>
using namespace std;

int main()
{


    double cena_bira = 0;
    double pari_djob = 0;
    int broi_biri = 0;

    cout << "cena bira = ";
    cin >> cena_bira;
    if (!cin)
    {
        cout << endl << "Greshna cena na birata, chao!" << endl;
    system("pause");
        return 1;
    }
    cout << cena_bira << endl;

    cout << "pari v djoba = ";
    cin >> pari_djob;
    if (!cin)
    {
        cout << endl << "Greshni pari v djoba, chao!" << endl;
    system("pause");
        return 1;
    }
    cout << pari_djob << endl;

    cout << "kolko shte izporkash = ";
    cin >> broi_biri;
    if (!cin)
    {
        cout << endl << "Greshen broi biri, chao!" << endl;
    system("pause");
        return 1;
    }
    cout << broi_biri << endl;

    if ( pari_djob >= (cena_bira * broi_biri) )
       {
           cout << "shte piesh " << broi_biri << " biri i shte ti ostanat " << pari_djob - (cena_bira * broi_biri) << " lv" << endl;
           cout << "da ti e sladko..." << endl;
       }
    else
       {
           if ( pari_djob / cena_bira > 1.0)
           {
              cout << "shte piesh samo " << floor(pari_djob / cena_bira) << " biri" << endl;
           }
           else
           {
                          cout << "nqma da piesh bira" << endl;
              cout << "obadi se na tate za pari (" << (cena_bira * broi_biri) - pari_djob << " lv)..." << endl;
           }
       }

   system("pause");
   return 0;
}