Kei's lab

lab2.cpp

//This is lab2 the vending machine creat by Kei Kato.

#include <iostream>
#include <iomanip>
#include <cstdlib>

#define PLURAL(variable, word) \
    variable << word << (variable > 1 ? "s" : "")

using namespace std;

int ChooseSnack(int numPotatoChips, int numCookies, int numCandies);
int PutCoins(string kindOfCoin);
int calTotal(int numQuaters, int numDimes, int numNickels);

int main(int argc, char** argv){

    const int pricePotatoChips = 125,
              priceCookies = 85,
              priceCandies = 95;

    if (argc != 4) {
        cerr << "ERROR: wrong number of arguments. Usage: " << argv[0]
             << " NUM_POTATOCHIPOS NUM_COOKIES NUM_CANDIES"
             << endl;
        return 1;
    }
    int numPotatoChips = atoi(argv[1]);
    int numCookies = atoi(argv[2]);
    int numCandies = atoi(argv[3]);
    if (numPotatoChips < 0 || numCookies < 0 || numCandies < 0) {
        cerr << "ERROR: Invalid number or non-numeric arguments: ['" 
             << argv[1] << "', '"
             << argv[2] << "', '"
             << argv[3] << "'] "
             << endl;
        return 1;
    }


    int customerChoice = 0;
    int numQuaters, numDimes, numNickels,
        numChangeQuaters, numChangeDimes, numChangeNickels;
    int price, total = 0, numSnack, change;

    //cout << numPotatoChips << numCookies << numCandies << endl;

    while (customerChoice != 4){
        //reset numbers
        numQuaters = 0;
        numDimes = 0;
        numNickels = 0;
        numChangeQuaters = 0;
        numChangeDimes = 0;
        numChangeNickels = 0;
        price = 0;
        total = 0;
        numSnack = 0;
        change = 0;

        // choose a snack
        customerChoice = ChooseSnack(numPotatoChips, numCookies, numCandies);
        switch (customerChoice){
            case 1 :
                price = pricePotatoChips;
                numSnack = numPotatoChips;
                numPotatoChips--;
                break;
            case 2 :
                price = priceCookies;
                numSnack = numCookies;
                numCookies--;
                break;
            case 3 :
                price = priceCandies;
                numSnack = numCandies;
                numCandies--;
                break;
            case 4 :
                cout << "Thank you!" << endl;
                break;
            default:
                cerr << "ERROR: unexpected error. Abort." << endl;
                return 1;
        }
        if(customerChoice == 4){
            break;
        }

        if(numSnack == 0){
            cout << "Sold out, please choose other snack." << endl;
            customerChoice = 0;
        }
        else{
            //put coins
            while(total < price){
                cout << "Please put coins." << endl;
                numQuaters = PutCoins("quaters");
                numDimes = PutCoins("dimes");
                numNickels = PutCoins("nickels");
                total += calTotal(numQuaters, numDimes, numNickels);

                if(total < price){
                    cout << price-total << " cnets more, please." << endl;
                }
            }

            if(total > price){
                //calculte change
                change = total-price;
                numChangeQuaters = change/25;
                change = change%25;
                numChangeDimes = change/10;
                change = change%10;
                numChangeNickels = change/5;
                cout << "Please take youa snack and change:" << endl;
                cout << PLURAL(numChangeQuaters, " quater") << endl;
                cout << PLURAL(numChangeDimes,   " dime")   << endl;
                cout << PLURAL(numChangeNickels, " nickel") << endl;
                cout << "Thank you!" << endl;
            }
            else{
                cout << "Please take your snack! Thank you!" << endl;
            }
        }
    }

    return 0;
}

int ChooseSnack(int numPotatoChips, int numCookies, int numCandies){
    int customerChoice;

    while (1) {
        cin.clear();
        cin.sync();
        cout << endl << "\t\t *** Please choose a snack from menu ***" << endl;
        cout << "1. Potato Chips $1.25\t" << PLURAL(numPotatoChips, " pack") << " available" << endl;
        cout << "2. Cookies      $0.85\t" << PLURAL(numCookies,     " pack") << " available" << endl;
        cout << "3. Candies      $0.95\t" << PLURAL(numCandies,     " pack") << " available" << endl;
        cout << "4. QUIT" << endl;
        cout << "Input: ";
        cin >> customerChoice;

        if (cin.eof()) {
            return 4; //better error handling?
        }
        if (cin.good()) {
            if(customerChoice < 1 || customerChoice > 4){
                cout << "Please type number 1 to 4." << endl;
            }
            else {
                return customerChoice;
            }
        } else {
            cout << "Error reading input. Please type number 1 to 4." << endl;
            cin.clear(); //clear the error
            cin.ignore(INT_MAX, '\n'); //clear the invalid input
        }
    }
}

int PutCoins(string kindOfCoin){
    usigned int numCoins;

    while(1){
        cout << "How many " << kindOfCoin << " ? ";
        cin >> numCoins;
        if (cin.eof()) {
            return 0; //FIXME: better aborting the program here.
        }
        if (cin.good()) {
            return numCoins;
        } else {
            cout << "Error reading input. Please input a number." << endl;
            cin.clear();
            cin.ignore(INT_MAX, '\n');
        }
    }
}

int calTotal(int numQuaters, int numDimes, int numNickels){
    int total;
    total = (numQuaters*25) + (numDimes*10) + (numNickels*5);
    return total;
}