Greek C++ Switch-SubProgram Examples

#include <iostream>

// Using nsp std to avoid using std:: prefix!
using namespace std;

// SUB-PROGRAMS

void add();
void subtraction();
void multiplication();
void division();

// GLOBAL VARIABLES

int oper;
long num1;
long num2;

// MAIN PROGRAM

int main()
{
    cout << "choose from the underneath nums to do a math operation:";
    cout << "1 for add";
    cout << "2 for sub";
    cout << "3 for mult";
    cout << "4 for div";

    cin >> oper;

    switch(oper)
        {
        case 1:
            add();
            break;
        case 2:
            subtraction();
            break;
        case 3:
            multiplication();
            break;
        case 4:
            division();
            break;
        default:
            exit;
            break;
        }

    system("pause");
    return 0;
}

void add()
{
    cout << "grapse enan ari8mo";
    cin >> num1;
    cout << "grapse enan allon ari8mo";
    cin >> num2;

    cout << "to a8roisma tous kanei : " << num1 + num2;

}
void subtraction()
{
    cout << "grapse enan ari8mo";
    cin >> num1;
    cout << "grapse enan allon ari8mo";
    cin >> num2;

    cout << "h diafora tous kanei : " << num1 - num2;

}
void multiplication()
{
    cout << "grapse enan ari8mo";
    cin >> num1;
    cout << "grapse enan allon ari8mo";
    cin >> num2;

    cout << "o pollaplasiasmos tous kanei : " << num1 * num2;

}
void division()
{
    cout << "grapse enan ari8mo";
    cin >> num1;
    cout << "grapse enan allon ari8mo";
    cin >> num2;

    cout << "h diairesh tous kanei : " << num1 / num2;

}