Code 1 - Pizza

#include<iostream>
using namespace std;

class Menu{

    private:

    public:
        void writeMenu(){
            cout<<"1. Order Pizza"<<endl;
            cout<<"2. Pay"<<endl;
            cout<<"3. Exit"<<endl;
        }
        void writePizzas(){
            cout<<"1. Meat lover pizza (@ Rp. 80000,-)"<<endl;
            cout<<"2. Vegetarian pizza (@ Rp. 50000,-)"<<endl;
            cout<<"Which pizza do you want to order[1-2]: ";
        }
};

struct data{
    int total;
}pizza1, pizza2;

int main(){

    system("cls");
    Menu menu;
    menu.writeMenu();
    int input;
    cin >> input;
    if(!cin){
        cin.clear();
        cin.ignore();
        main();
    } else {
        switch(input){
            case 1:

                STARTHERE:
                    menu.writePizzas();
                    cin>>input;
                    if(!cin){
                        cin.clear();
                        cin.ignore();
                        system("cls");
                        goto STARTHERE;
                    } else {
                        switch(input){
                            case 1:

                                ++pizza1.total;
                                break;
                            case 2:

                                ++pizza2.total;
                                break;

                            default:
                                goto STARTHERE;
                                break;
                        }
                    }
                    cout<<"Thank you..."<<endl;
                    main();
                break;

            case 2:

                if(pizza1.total > 0 || pizza2.total > 0){
                    cout<<"You have ordered "<<pizza1.total<<" Meat Lover Pizza(s) and "<<pizza2.total<<" Vegetarian Pizza(s)."<<endl;
                    cout<<"Total price : "<<(pizza1.total*80000)+(pizza2.total*50000)<<endl;

                    ASKMONEY:
                        cout<<"Input your money [minimum Rp. "<<(pizza1.total*80000)+(pizza2.total*50000)<<"] :";
                        cin>>input;
                        if(!cin){
                            cin.clear();
                            cin.ignore();
                            system("cls");
                            goto ASKMONEY;
                        } else {
                            if(input>=(pizza1.total*80000)+(pizza2.total*50000)){
                                cout<<"Your change : Rp. "<<input-(pizza1.total*80000)+(pizza2.total*50000)<<endl;
                                cout<<"Thank you..."<<endl;
                                cin.clear();
                                cin.ignore();
                                getchar();
                            }
                        }
                } else {
                    cout<<"You are not buy anything.."<<endl;
                    cin.clear();
                    cin.ignore();
                    getchar();
                }

                main();
                break;

            case 3:

                cout<<"Thank you..."<<endl;
                exit(0);
                break;

            default: break;
        }
    }
}