计算美元就在货币改革计划 - C++

Question

请看看下面的代码

#include <QtCore/QCoreApplication> 
#include <iostream> 

int main(int argc, char *argv[]) 
{ 
    using namespace std; 

    double purchaseAmount; 
    double paidAmount; 
    float balance; 

    int change, quarters, dimes, nickels, pennies, tenDollar, fiveDollar; // declare variables 

    cout << "Enter Total purchased amount" << endl; 
    cin >> purchaseAmount; 

    cout << "Enter Total paid amount" << endl; 
    cin >> paidAmount; 

    balance = paidAmount - purchaseAmount ; 

    tenDollar = balance/10; // calculate the number of Ten Dollars 
    change = tenDollar % 10 ; // calculate the change needed 
    change = balance * 100; 
    quarters = change/25; // calculate the number of quarters 
    change = change % 25; // calculate remaining change needed 
    dimes = change/10; // calculate the number of dimes 
    change = change % 10; // calculate remaining change needed 
    nickels = change/5; // calculate the number of nickels 
    pennies = change % 5; // calculate pennies 

    cout << "\nQuarters: " << quarters << endl; // display # of quarters 
    cout << " Dimes: " << dimes << endl; // display # of dimes 
    cout << " Nickels: " << nickels << endl; // display # of nickels 
    cout <<" Pennies: " << pennies << endl; // display # of pennies 
    cout <<" Ten dollar: " << tenDollar << endl; // display # of Ten dollar 
    //cout <<" Five dollar: " << fiveDollar << endl; // display # of Ten dollar 

    return (0); 

} 

我想在这里做，计算剩下十块钱，宿舍，硬币，镍的变化和便士。例如，当我用这种方式运行程序 -

Enter Total purchased amount 
9.75 
Enter Total paid amount 
20 

Quarters: 4 
Dimes: 0 
Nickels: 0 
Pennies: 0 
Ten dollar: 1 

这是错误的。这就是说，上面的输出是错误的。相反它应该是

Enter Total purchased amount 
9.75 
Enter Total paid amount 
20 

Quarters: 1 
Dimes: 0 
Nickels: 0 
Pennies: 0 
Ten dollar: 1 

那么我在这里做错了什么？

感谢

Answer 1

没有太大变化你的代码，你可以通过更换

change = balance * 100; 

与

change = ((balance) - floor(balance)) * 100; 

然而，把更多的想进入你的解决方案得到您想要的答案，而且我保证你会得到更多的积分，而不是简单的解决方法。另外，你不敢打破约定，请使用名称空间标准以外的主要位置您的。

像这样：

#include <iostream> 
using namespace std; // Place it here! Not inside main. 

int main() 
{ 
return 0; 
} 

注：我说想要的答案。

Answer 2

正如人们一再说过的，错误在于痛苦的重复代码。考虑以下几点：

int currencyCount(int& pennies, int penniesInDenomination) { 
    const int count = penniesInBase/penniesInDenomination; 
    pennies = pennies % penniesInDenomination; 

    return count; 
} 

这可以用于每个面额 - 重复和一行。这可以通过让函数得到两个值：新的余额和该面额的计数。这种做法通过引用平衡来作弊，并且作为将此称为独立功能的“副作用”，它会根据返回的面额数量减少余额。很明显，你会想记录这一点。

... 
const int numberOfQuarters = currencyCount(balance, 25); 
const int numberOfDimes = currencyCount(balance, 10); 
... 

你也可以把货币信息（如姓名和便士它所代表的数量）超过它的载体和循环中执行同样的事情：

typedef std::pair<std::string, int> Currency; 
typedef std::vector<Currency> Currencies; 
typedef Currencies::const_iterator CIter; 

... 

for(CIter iter = currencies.begin(); iter != currencies.end(); ++iter) { 
    const int quantity = currencyCount(balance, iter->second); 
    std::cout << iter->first << ": " << quantity << std::endl; 
} 

以这种方式，你避免了重复的代码和它涉及的错误。