CS50 Pset1 现金 : "undefined reference to ' get_change'"

Question

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

int main(void)
{
    // prompt user for "0.00" value
    float dollars;
    double get_change(float dollars);
        // prompt user for "0.00" value
    do
        {
            dollars = get_float("Change owed: ");
        }
    while(dollars <= 0);
    printf("%f\n", get_change(dollars));

        //calculate which coins will be used
    int cents = round(dollars * 100);
    int coins = 0;
    int denom[] = {25, 10, 5, 1};

    for (int i = 0; i < 4; i++)
        {
            coins += cents / denom[i];
            cents = cents % denom[i];
        }
    return coins;
}

在 CS50 中进行 Pset1 现金。收到错误消息“在函数 main”中:
/home/ubuntu/workspace/pset1/cash/cash2.c:15: undefined reference get_change'clang:错误:链接器命令失败，退出代码为 1(使用 -v 查看调用)make: [cash2] 错误 1"非常困惑

Answer 1

以下建议代码:

1. 执行所需硬币总数的操作(假设没有纸币)
2. 正确分离功能
3. 正确使用子函数的原型(prototype)
4. 正确地从float转换为int
5. 通过包含小数点和尾随“f”，正确地将常量定义为 float

现在，建议的代码:

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

int get_change( float dollars );


int main(void)
{
    // prompt user for "0.00" value
    float dollars;

    do
    {
        dollars = get_float("Change owed: ");
    }
    while(dollars <= 0.0f);

    printf("%d\n", get_change(dollars));
}

// returns number coins needed, not their denominations 
int get_change( float dollars )
{
    //calculate which coins will be used
    int cents = (int)floorf(dollars * 100.0f);
    int coins = 0;
    int denom[] = {25, 10, 5, 1};

    for (int i = 0; i < 4; i++)
    {
        coins += cents / denom[i];
        cents = cents % denom[i];
    }
    return coins;
}