我试图找出程序在循环中运行的原因。我只是看不出它是如何开始循环的。想给你更多的信息，但只是运行代码并做正确的事情，程序只是重新开始，但不是在开头。它将从我选择付款选项时开始。 这是代码，代码是c ++：
#include <iostream>
#include <functional>
using namespace std;
int option, pause, payment, selection, zipcode, error, pin, quantity_chips, quantity_milk, quantity_cola,
quantity_coffee, quantity_pennies, quantity_nickels, quantity_dimes, quantity_quarters, quantity_dollars,
quantity_fives, quantity_tens, quantity_twenties, quantity_total;
float chips, milk, cola, coffee, total, tax, final_cost, pennies, nickels, dimes, quarters,
dollars, fives, tens, twenties, cash_total, owed, change;
void checkout(), debitcard (), creditcard (), cash (), receipt ();
void menu ()
{
cout << "Welcome to Kenjin Xer0's Item Pooper.\n"
<< "10 or less items.\n";
do
{
quantity_total = (quantity_chips) + (quantity_milk) + (quantity_cola) + (quantity_coffee);
cout << "Select from our menu: Selected\n"
<< "\t1. Potato Chip.....$1.50......" << quantity_chips << "\n"
<< "\t2. 2% Milk.........$2.00......" << quantity_milk << "\n"
<< "\t3. Off Brand Cola..$1.00......" << quantity_cola << "\n"
<< "\t4. Dark Coffee.....$2.50......" << quantity_coffee << "\n"
<< "\t5. Check out Total:" << quantity_total << "\n";
cout << "Enter your option: ";
cin >> option;
if (option == 1)
{
cout << "Quantity: ";
cin >> quantity_chips;
chips = (1.5 * quantity_chips);
}
else if (option == 2)
{
cout << "Quantity: ";
cin >> quantity_milk;
milk = (2 * quantity_milk);
}
else if (option == 3)
{
cout << "Quantity: ";
cin >> quantity_cola;
cola = (1 * quantity_cola);
}
else if (option == 4)
{
cout << "Quantity: ";
cin >> quantity_coffee;
coffee = (2.5 * quantity_coffee);
}
else if (option == 5)
{
if (total > 10)
{
cout << "Problem! 10 or less line, Man!\n";
option = 0;
}
else
{
checkout();
}
}
else
{
cout << "Invalid option.\n";
}
}
while (option !=5);
}
void checkout ()
{
do
{
cout << "Select payment option (1:Debit 2:Credit 3:Cash): ";
cin >> payment;
if (payment == 1)
{
debitcard ();
}
else if (payment == 2)
{
creditcard ();
}
else if (payment == 3)
{
cash ();
}
else
{
cout << "Weird Choice, try again.\n";
}
}
while (payment != 1||2||3);
}
void debitcard ()
{
error = 3;
do
{
error--;
cout << "Enter PIN:\n";
cin >> pin;
if (error == 0)
{
cout << "We are sorry but does this card acually belong to you.\n"
<< "Now Leave.\n";
break;
}
else if (pin != 0000)
{
cout << "Wrong. Try Again\n"
<< "You now have " << error << " more tries\n";
}
else
{
receipt();
}
}
while (pin != 0000);
}
void creditcard ()
{
error = 3;
do
{
error--;
cout << "Enter Zip:\n";
cin >> zipcode;
if (error == 0)
{
cout << "We are sorry but does this card acually belong to you.\n"
<< "Now Leave.\n";
break;
}
else if (zipcode != 77523)
{
cout << "Wrong. Try Again\n"
<< "You now have " << error << " more tries\n";
}
else
{
receipt();
}
}
while (zipcode != 77523);
}
void cash ()
{
total = (chips) + (milk) + (cola) + (coffee);
tax = (total * .10);
final_cost = tax + total;
cout << "You owe $"<< final_cost <<".\n";
do
{
cash_total = (pennies) + (nickels) + (dimes) + (quarters) + (dollars) + (fives) + (tens) + (twenties);
owed = final_cost - cash_total;
cout << "Select the Amount:\n"
<< "\t1. Penny................$0.01......" << quantity_pennies << "\n"
<< "\t2. Nickel...............$0.05......" << quantity_nickels << "\n"
<< "\t3. Dime.................$0.10......" << quantity_dimes << "\n"
<< "\t4. Quarter..............$0.25......" << quantity_quarters << "\n"
<< "\t5. One Dollar Bill......$1.00......" << quantity_dollars << "\n"
<< "\t6. Five Dollars Bill....$5.00......" << quantity_fives << "\n"
<< "\t7. Ten Dollar Bill......$10.00....." << quantity_tens << "\n"
<< "\t8. Twenty Dollar Bill...$20.00....." << quantity_twenties << "\n"
<< "\t9. Cash Out\n"
<< "Cash you Have: $" << cash_total << " Still owe: $" << owed << "\n";
cout << "Enter your selection: ";
cin >> selection;
if (selection == 1)
{
cout << "Quantity: ";
cin >> quantity_pennies;
pennies = (0.01 * quantity_pennies);
}
else if (selection == 2)
{
cout << "Quantity: ";
cin >> quantity_nickels;
nickels = (0.05 * quantity_nickels);
}
else if (selection == 3)
{
cout << "Quantity: ";
cin >> quantity_dimes;
dimes = (0.10 * quantity_dimes);
}
else if (selection == 4)
{
cout << "Quantity: ";
cin >> quantity_quarters;
quarters = (0.25 * quantity_quarters);
}
else if (selection == 5)
{
cout << "Quantity: ";
cin >> quantity_dollars;
dollars = (1.00 * quantity_dollars);
}
else if (selection == 6)
{
cout << "Quantity: ";
cin >> quantity_fives;
fives = (5.00 * quantity_fives);
}
else if (selection == 7)
{
cout << "Quantity: ";
cin >> quantity_tens;
tens = (10.00 * quantity_tens);
}
else if (selection == 8)
{
cout << "Quantity: ";
cin >> quantity_twenties;
twenties = (20.00 * quantity_twenties);
}
else if (selection == 9)
{
receipt ();
}
else
{
cout << "Invalid option.\n";
}
}
while (selection != 9);
}
void receipt ()
{
total = (chips) + (milk) + (cola) + (coffee);
tax = (total * .10);
final_cost = tax + total;
change = owed * -1;
cout << "Receipt Take:\n";
if (quantity_chips > 0)
{
cout << "Potato Chips: $1.50 x " << quantity_chips << " = $" << chips << endl;
}
if (quantity_milk > 0)
{
cout << "2% Milk: $2.00 x " << quantity_milk << " = $" << milk << endl;
}
if (quantity_cola > 0)
{
cout << "Off Brand Cola: 1.00 x " << quantity_cola << " = $" << cola << endl;
}
if (quantity_coffee > 0)
{
cout << "Dark Coffee: $2.50 x " << quantity_coffee << " = $" << coffee << endl;
}
cout << "Tax (10.0%): $" << tax << endl;
cout << "Total: $" << final_cost << endl;
cout << "Change Returned: $" << change << endl;
}
int main ()
{
menu ();
return 0;
}
答案 0 :(得分：0)
checkout()中的while循环不正确。你有：
while (payment != 1||2||3);
这不是你怎么做的多或多。你需要把它写成
while (payment != 1 || payment != 2 || payment != 3);
答案 1 :(得分：0)
在你的结帐功能 取代
while (payment != 1||2||3)
通过
while (payment != 1 && payment != 2 && payment != 3)
答案 2 :(得分：0)
要删除您在checkout函数中退出do-while循环所做的一系列令人困惑的条件，可以这样做：
void checkout ()
{
bool choice_made;
do
{
choice_made = true;
cout << "Select payment option (1:Debit 2:Credit 3:Cash): ";
cin >> payment;
if (payment == 1)
{
debitcard ();
}
else if (payment == 2)
{
creditcard ();
}
else if (payment == 3)
{
cash ();
}
else
{
cout << "Weird Choice, try again.\n";
choice_made = false;
}
}
while (!choice_made);
}
您只能退出循环，直到做出有效选择。只需一个简单的布尔值就可以控制逻辑。
关于你的尝试，这一行：
while (payment != 1||2||3)
将逻辑or应用于1,2和3的值。结果始终为true，即1。所以归结为
while (payment != 1)