Question

using namespace std;

int amount_total(int amount_paid, int& amountleft), quarters(int&
    amountleft), dimes(int& amountleft), pennies(int& amountleft);

int amount_total(int amount_paid, int& amountleft)
{
    const int TOTALVALUE = 99;

    cout << "You have bought a candy bar that's 99 cents. \n"
        << "Please insert the amount paid. " << endl;
    cin >> amount_paid;
    amountleft = TOTALVALUE - amount_paid;

    cout << "You have to pay : " << amountleft << " cents. \n" << endl;

    return(0);
}

int quarters(int& amountleft)
{
    const int QUARTERS = 25;
    int total, count_Quarters;
    count_Quarters = 0;

    while (amountleft > 0 || amountleft >= QUARTERS)
    {
        total = amountleft - QUARTERS;

        count_Quarters++;
    }

    return(count_Quarters);
}

int dimes(int& amountleft)
{
    const int DIMES = 10, QUARTERS = 25;
    int total, count_Dimes;
    count_Dimes = 0;

    while (amountleft > 0 || amountleft <= QUARTERS)
    {
        total = amountleft - DIMES;

        count_Dimes++;
    }

    return(count_Dimes);
}

int pennies(int& amountleft)
{
    const int PENNIES = 1, DIMES = 10;
    int total, count_Pennies;
    count_Pennies = 0;

    while (amountleft >= 0 || amountleft <= DIMES)
    {
        total = amountleft - PENNIES;

        count_Pennies++;
    }

    return(count_Pennies);
}

int main()
{
    int amount_paid, amountleft, Count_Quarters,
        Count_Dimes, Count_Pennies, total_amount;

    total_amount = amount_total(amount_paid, amountleft);
    Count_Quarters = quarters(amountleft);
    Count_Dimes = dimes(amountleft);
    Count_Pennies = pennies(amountleft);

    cout << "You'll get : " << Count_Quarters << " quarters, " <<
        Count_Dimes << " dimes, and " << Count_Pennies << " pennies. \n"
        << endl;
    return 0;
}

//示例运行：

你买了一个99美分的糖果吧。请输入已付金额。 36 你必须支付：63美分。

我最初的计划是运行程序，主程序只运行函数，函数会返回变量，但它没有这样做而且它只运行第一个函数

Answer 1

正如评论中提到的rex所有的while循环都是无限的，所以永远不会停止循环。你的程序在你的第二个功能“宿舍”内实现冻结。看看那里的事情如何：当你离开你的函数amount_total时，它返回0并将它分配给一个“total_amount”变量，之后它已经为“amountleft”变量赋值等于“TOTALVALUE - amount_paid”。您将此值（在“amountleft”变量内）传递给第二个函数“quarters”。如果您的示例“amountlef”变量等于63，它大于“0”并且也大于QUARTERS（因为它是25）。所以你在这里开始循环并且循环的每次迭代你的变量“amountleft”保持具有相同的值，即63，因为它在你的while循环内没有改变，留下你必须改变“amountleft”的循环或者设置任何类型的休息。为了使它更加可见，可以在循环中设置“cout”，看看那里发生了什么。像这样。

 21 int quarters( int& amountleft ) {                                                                                                  
 22         const int QUARTERS = 25;                                                                                                   
 23         int total, count_Quarters;                                                                                                 
 24         count_Quarters = 0;                                                                                                        
 25         cout << "before while-loop" << endl;                                                                                       
 26         while( amountleft > 0 || amountleft >= QUARTERS ) {
 27           cout << "count_Quarters = " << count_Quarters  << endl;
 28           cout << "amountleft  = " << amountleft  << endl;                                                                         
 29                 total = amountleft - QUARTERS;                                                                                     
 30                                                                                                                                    
 31                 count_Quarters++;                                                                                                  
 32         }                                                                                                                                                                                                                                                   
 33         cout << "after while-loop" << endl;                                                                                        
 34         return count_Quarters;                                                                                                     
 35 }

请记住，由于您尚未定义“total”变量，因此它可以包含任何垃圾，但通常不会。无论如何，在使用它之前将任何值（例如0等）分配给变量可能是好的。

关于函数调用，我的程序不是在阅读我的其他函数。为什么？

1 个答案: