C代码错误不是函数或函数指针

Question

我有以下 C 代码。当我尝试编译它时，我收到一条错误消息:

called object 'countPassed' is not a function or function pointer"

我该如何解决这个问题？

#include <stdio.h>

int main()
{
    int countWhoPassed, averageCalculate, printPassed;
    int amount = howManygrades();
    storesGrades(amount);
    printAll(amount);
    averageCalculate = averageCalc(amount);
    printAverage(amount);
    countWhoPassed = countPassed(amount);
    printPassed = printWhoPassed(amount);
    return 0;
}

int howManygrades()
{
    int gradesAmount;
    printf("How many grades do you want?\n");
    scanf("%d", &gradesAmount);
    while (gradesAmount > 10) {
        printf("Sorry, this amount of numbers is too big for the array.");
        scanf("%d", &gradesAmount);
        while (gradesAmount < 0) {
            printf("Sorry, this amount of numbers is too small for the array.");
            scanf("%d", &gradesAmount);
        }
    }
    while (gradesAmount < 0) {
        printf("Sorry, this amount of numbers is too small for the array.");
        scanf("%d", &gradesAmount);
        while (gradesAmount > 10) {
            printf("Sorry, this amount of numbers is too big for the array.");
            scanf("%d", &gradesAmount);
        }
    }

    return gradesAmount;
}

void storesGrades(int amount)
{
    int iterator;
    float grade;
    for (iterator = 0; iterator < amount; iterator++)
    {

        printf ("Enter another grade.");
        scanf("%f", &grade);
        while ((grade <= 0.0) || (grade > 10.0))
        {
            printf("Sorry, this number is not valid.");
            scanf("%f", &grade);
        }
        grades[iterator] = grade;
    }
}

void printAll(int amount)
{
    int iterator;
    for (iterator = 0; iterator < amount; iterator++)
    {
        printf("%.1f\n", grades[iterator]);
    }
}

int averageCalc(int amount)
{
    float sum, averageResult, average;
    int iterator;
    sum = 0.0;
    for (iterator = 0; iterator < amount; iterator++) {
        sum += grades[iterator];
    }
    average = sum / (float)amount;
    return average;
}

void printAverage(int amount)
{
    float printThisAverage = averageCalc(amount);
    printf("%.2f", printThisAverage);
}

int countPassed(int amount)
{
    int iterator, countPassing;
    countPassing = 0;
    for (iterator = 0; iterator < amount; iterator++)
    {
        if (grades[iterator] >= 5.5)
        {
            countPassing++;
        }
    }
    return countPassing;
}

int printWhoPassed(int amount)
{
    int returnValue = countPassed(amount);
    return returnValue;
}

Answer 1

似乎有几个问题。我认为您收到的错误消息很奇怪，它应该说 countPassed 未定义。那是因为你在调用它之后定义它。您可以通过在调用函数之前添加函数原型(prototype)来修复它。通过这种方式，您可以告诉编译器函数的存在(还没有定义函数)并且它会编译。对我来说，它的工作原理是将以下原型(prototype)添加到您的代码中，放在主要部分之前:

int countPassed(int amount);
void printAll(int amount);
void printAverage(int amount);
void storesGrades(int amount);

或者，您可以将 main 函数放在所有其他函数之后。当然，这在实际项目中并不总是一个选项。

此外，grades 没有定义。我假设您想要一个 int 数组，所以添加类似 int grades[10] 的东西应该可以解决问题(在这个例子中，最多可以使用 10 个等级，它也可能动态分配该内存以允许用户想要的任何数量)。

此外，我还必须添加 #include "stdio.h" 以使其与 printf 一起编译，尽管有些编译器不会介意它是否丢失。