c++ - 如何可以根据需要多次执行我的功能？

Question

我有一个学校项目和一个简单的自动售货机。我想知道如何根据用户的需要多次执行我的功能，同时跟踪机器内部的可用变化。

#include <iostream>
#include <string>
using namespace std;
void changecalculator (int purchaseAmount, int& Qav, int& Dav, int& Nav)
{
    int QBack ,DBack ,NBack ;
    int chaneBack = 100 - purchaseAmount ;

    if (purchaseAmount %5 == 0)
    {
        cout << "You entered a purchase amount of " << purchaseAmount << " cents." <<endl;
        cout <<endl;
        QBack = std::min(chaneBack / 25, Qav) ;
        chaneBack -= QBack * 25 ;
        DBack = std::min(chaneBack/10, Dav);
        chaneBack -= DBack* 10;
        NBack = std::min(chaneBack/ 5, Nav);
        chaneBack = QBack*25 + NBack*10 + DBack*5 ;
        int coinsNum = QBack + DBack + NBack;
        cout <<"Your change of " <<chaneBack <<" cents is given as " <<QBack <<" Q, " <<DBack <<" D,and " <<NBack <<" N." <<endl;
        cout << "The value of your " <<coinsNum <<" coins adds up to " <<chaneBack <<" cents." <<endl;
        cout << "Thank you for using my program." <<endl;
        Qav -= QBack;
        Dav -= DBack;
        Nav -= NBack;
        cout << "Quarters available: " <<Qav <<endl;
        cout << "Dimes available: " <<Dav <<endl;
        cout << "Nickels available: " <<Nav <<endl;



    }
    else
    { 
        cout << "Unable to process an invalid purchase amout of " <<purchaseAmount <<" cents." <<endl;
        cout << "Thank you for using my program." <<endl;

    }
}
int main()
{
    //set the variables
    int Qav=5 ;
    int Dav=5 ;
    int Nav=5 ;
    int purchaseAmount ;
    string answer;
    cout << "Simple Vending Program for Adam Ashouri (Regular Version)" <<endl;
    cout <<endl;
    cout <<endl;
    cout << "Enter a purchase amount [5 - 100] -->";
    cin >> purchaseAmount;

    changecalculator (purchaseAmount, Qav, Dav, Nav);
    cout << "Process again (y/n)?";
    cin >> answer;
}

Answer 1

类似于 do{} while() 循环？

do 
{
    cout << "Simple Vending Program for Adam Ashouri (Regular Version)" <<endl;
    cout <<endl;
    cout <<endl;
    cout << "Enter a purchase amount [5 - 100] -->";
    cin >> purchaseAmount;

    changecalculator (purchaseAmount, Qav, Dav, Nav);
    //get userResponse;
}
while(userResponse =='y' || userResponse =='Y');