c++ - 我不知道如何让我的程序使用局部变量而不是全局变量

Question

我的程序需要使用局部变量而不是全局变量。然而，当我尝试这样做时，我似乎无法找到正确的参数来从 main 和函数来回传递数据。我不断收到错误消息“int 的参数类型与 float 类型的参数不兼容”。请帮助我了解在这里该怎么做。感谢您抽出宝贵的时间，我很感激。

我尝试用谷歌搜索错误代码，但只能找到有关我尚未了解的指针问题的答案/问题。 我已经研究了几个小时，只是为了让变量在“int main”中工作，但没有成功。

//This program asks user how many grades there are, 
//inputs grades, and displays median of said grades.

//"int main" is at the bottom of the program, preceded by
//variables, function headers, and a single array.
#include <iostream>
using namespace std;

void grdTaker(float [], int);
void sortArray(float[], int);
void median(float[], int);

//Main
int main()
{
    //Variables
//int grdsCounted; //Number of grades from user.
    const int arraySize = 20;
    int grdsCounted; //Number of grades from user.
    float grades[arraySize]; //Max grades that can be entered.

    grdTaker(grdsCounted, grades[]);
    sortArray(grades, grdsCounted);
    median(grades, grdsCounted);

    system("pause");
}

void grdTaker(float array[], int size) //Function gathers grades.
{
    //const int arraySize = 20;
    //int grdsCounted; //Number of grades from user.
    //float grades[arraySize]; //Max grades that can be entered.

    cout << "You may input up to 20 grades. \n";
    cout << "First enter the number of grades you have: ";
    cin >> grdsCounted;

    while (grdsCounted > arraySize)
    {
        cout << "That is more than 20 grades, try again: \n";
        cin >> grdsCounted;
    }

    cout << "Enter each grade: \n";

    //requests how many grades there are and stores them in array
    for (int grdCount = 0; grdCount < grdsCounted; grdCount++)
    {
        cin >> grades[grdCount];
    }
};

void sortArray(float array[], int size) //Function sorts array values.
{
    bool swap;
    float temp;

    do
    {
        swap = false;
        for (int count = 0; count < (size - 1); count++)
        {
            if (array[count] > array[count + 1])
            {
                temp = array[count];
                array[count] = array[count + 1];
                array[count + 1] = temp;
                swap = true;
            }
        }
    } while (swap);
}

void median(float array[], int size) //Outputs the median of entered grades.
{
    int med = size / 2;
    int odd = med - 1;

    cout << "The median grade is: ";

    if (size % 2 == 1)
    {
        cout << array[med] << endl;
    }
    else
    {
        cout << (array[med] + array[odd]) / 2 << endl;
    }

}

Answer 1

您分配给 float 的问题可能是由于在 C++ 中以这种方式创建数组造成的。尝试使用 new 以 de C++ 方式声明数组。

你有没有想过返回这些值!看看这个!例如，将第一个函数分成2!编程总是将问题分解成小问题。

int numberGradesFromUser() {

    int grdsCounted;
    int arraySize = 20;

    cout << "You may input up to 20 grades. \n";
    cout << "First enter the number of grades you have: ";
    cin >> grdsCounted;

    while (grdsCounted > arraySize)
    {
        cout << "That is more than 20 grades, try again: \n";
        cin >> grdsCounted;
    }
    return grdsCounted;
}

float* grdTaker(int grdsCounted) //Function gathers grades.
{

    float * grades = new float[grdsCounted];

    cout << "Enter each grade: \n";

    //requests how many grades there are and stores them in array
    for (int grdCount = 0; grdCount < grdsCounted; grdCount++)
    {
        cin >> grades[grdCount];
    }
    return grades;

};

int main()
{
    //Variables

    int grdsCounted; //Number of grades from user.      

    grdsCounted = numberGradesFromUser();
    float *gradess = new float[grdsCounted];

    sortArray(gradess, grdsCounted);
    median(gradess, grdsCounted);

    system("pause");
}

有了这个，我想其余的功能应该可以工作了。按照您的方式调整它们!

此外，最好在 header 中声明函数，或者至少在主函数的顶部而不是下面!