运行我的函数时，它不会返回我一个值，我做错了什么？

至少在函数中，你有一个 inifinte while 循环，当大于calculate_quarterscents24

int calculate_quarters(int cents)
{
    // TODO
    int quaters;
    while(24<cents)
    {
        quaters = cents/25;
    }
    return quaters;
}

因为变量没有被更改。看来您需要简单地定义函数cents

int calculate_quarters(int cents)
{
    return cents / 25;
}

其他函数（如 、 和 ）也存在类似的问题。calculate_dimescalculate_nickelscalculate_pennies

而这个电话

// Calculate the number of pennies to give the customer
int pennies = calculate_pennies( cents );

只是多余的。

此外，请尝试使用命名常量而不是幻数，例如 .25

请注意，与其对变量使用有符号类型，不如使用无符号整数类型来防止使用负值。intunsigned int

如果使用该类型，那么您的程序看起来更简单，而无需通过标头中声明的标准 C 函数来定义函数intdiv<stdlib.h>

例如

#include <stdlib.h>

//...


// Calculate the number of quarters to give the customer 
div_t result = div( cents, 25 );
int quarters = result.quot;
cents = result.rem;

// Calculate the number of dimes to give the customer
result = div( cents, 10 );
int dimes = result.quot;
cents = result.rem;

// and so on

在这种情况下，您的程序可能如下所示

#include <stdio.h>
#include <stdlib.h>
#include <cs50.h>    

int get_cents( void )
{
    int cents;

    do
    {
        cents = get_int( "Change Owed: " );
    } while (cents < 0);

    return cents;
}

int main( void )
{
    const int CENTS_PER_QUATER = 25;
    const int CENTS_PER_DIME   = 10;
    const int CENTS_PER_NICKEL = 5;

    // Ask how many cents the customer is owed
    int cents = get_cents();

    // Calculate the number of quarters to give the customer
    div_t result = div( cents, CENTS_PER_QUATER );
    int quarters = result.quot;
    cents = result.rem;

    // Calculate the number of dimes to give the customer
    result = div( cents, CENTS_PER_DIME );
    int dimes = result.quot;
    cents = result.rem;

    // Calculate the number of nickels to give the customer
    result = div( cents, CENTS_PER_NICKEL );
    int nickels = result.quot;
    cents = result.rem;

    // Calculate the number of pennies to give the customer
    int pennies = cents;

    // Sum coins
    int coins = quarters + dimes + nickels + pennies;

    // Print total number of coins to give the customer
    printf( "%d\n", coins );
}

计算函数中的逻辑没有正确划分硬币。您设置的 while 循环将无限继续，因为美分的值在循环中永远不会改变。相反，您可以简单地使用整数除法来计算硬币的数量并返回该值。除法的其余部分（给硬币后剩下的零钱）将在主函数中处理，因为您已经设置好了。

以下是更正后的代码：

#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);

    // Sum coins
    int coins = quarters + dimes + nickels + pennies;

    // Print total number of coins to give the customer
    printf("%i\n", coins);
}

int get_cents(void)
{
    int cents;
    do{
        cents = get_int("Change Owed: ");
    }
    while (cents<0);
    return cents;
}

int calculate_quarters(int cents)
{
    return cents / 25;
}

int calculate_dimes(int cents)
{
    return cents / 10;
}

int calculate_nickels(int cents)
{
    return cents / 5;
}

int calculate_pennies(int cents)
{
    return cents / 1;
}

该程序将正确计算作为零钱提供的最小硬币数量。它首先计算最大四分之一数，然后计算剩余零钱的最大一角硬币数，然后是镍币，最后是便士。