c-CS50 pset 1现金问题:代码返回异常巨额

Question

我刚刚参加了CS50课程，正在与Pset 1作斗争。这是我的代码：

#include <cs50.h>
#include <stdio.h>
int get_cents(void);
int calculate_quarters(int cents);
int calculate_dimes(int cents);
int calculate_nickels(int cents);
int calculate_pennies(int cents);
int main(void)
{
    // Ask how many cents the customer is owed
    int cents = get_cents();
    // Calculate the number of quarters to give the customer
    int quarters = calculate_quarters(cents);
    cents = cents - quarters * 25;
    // Calculate the number of dimes to give the customer
    int dimes = calculate_dimes(cents);
    cents = cents - dimes * 10;
    // Calculate the number of nickels to give the customer
    int nickels = calculate_nickels(cents);
    cents = cents - nickels * 5;
    // Calculate the number of pennies to give the customer
    int pennies = calculate_pennies(cents);
    cents = cents - pennies * 1;
    // Sum coins
    int coins = quarters + dimes + nickels + pennies;
    // Print total number of coins to give the customer
    printf("%in", quarters);
}
int get_cents(void)
{
    int owed;
    do
    {
        owed = get_int("Change owed: ");
    } while (owed<=0);
    return owed;
}
int calculate_quarters(int cents)
{
    int n;
    while (cents <= 25)
    {
        n++;
        cents = cents - 25;
    }
    return n;
}
int calculate_dimes(int cents)
{
    int n;
    while (cents <= 10)
    {
        n++;
        cents = cents - 10;
    }
    return n;
}
int calculate_nickels(int cents)
{
    int n;
    while (cents <= 5)
    {
        n++;
        cents = cents - 5;
    }
    return n;
}
int calculate_pennies(int cents)
{
    int n;
    while (cents <= 1)
    {
        n++;
        cents = cents - 1;
    }
    return n;
}

该代码返回大量类似于"；277258257"；。问题出在函数上，但我不知道它是什么。当我在主函数中使用相同的while循环而不是创建函数时，它可以完美地工作(但它不符合练习要求，因为CS50机器人也会检查代码中是否存在这些函数(。

对不起我的英语，我的主要语言是法语，有时我会说一些奇怪的话。如果我说的任何话都没有意义，请告诉我。

Answer 1

在以下中

int n;
/* ... */
n++

n未初始化，包含一个不确定的值。有时被称为垃圾值，该值实际上是随机的。在n++中使用此值会调用Undefined Behavior。

初始化每个变量。

int n = 0;

---

用于计算硬币的每个while循环都使用了错误的运算符。更改

while (cents <= 25)

至

while (cents >= 25)

其他人也是如此。

---

coins未使用。更改

printf("%in", quarters);

至

printf("%in", coins);