移动类以分离 .cpp 和 .h 文件时遇到问题。

Question

我创建了一个基本的 consol 程序，它创建了一个用户想要的高度和宽度的盒子。我想了解类是如何工作的，所以我只使用了一个文件。现在我正在尝试将类正确放入 .h 和 .cpp 文件中。有人可以指出我做错了什么以及我应该如何解决它？

只有 main.cpp 的原始代码：

#include "stdafx.h"
#include <iostream>
using namespace std;

class BoxClass {
    //prv variables
    unsigned short int width;
    int height, i;
    float space_Value;
    float height_Count = 1;
    bool error = false;

    //prv functions
    void Print_Rectangle(int x, int y) {

        //calc
        space_Value = (3 * x) - 4;

        //draw top of box
        for (width = 1; width < x; width += 1) {
            cout << "...";
        }
        cout << "\n";

        //draw sides
        for (height = 1; height < y; height += 1) {
            cout << ":";
            height_Count++;
            for (width = 1; width < space_Value; width += 1) {
                cout << " ";
            }

            cout << ":\n";
        }

        //draw bottom
        cout << ":";

        for (width = 1; width < space_Value; width += 1) {
            cout << ".";
        }
        cout << ":\n";
    }

public:
    //function shows area of individual spaces
    float Rectangle_Area() {
        if (error == false) {
            return (height_Count - .5)*(space_Value - 1);
        }
        else {
            return 0;
        }
    }
    //function shows area of individual spaces

    // constructor
    BoxClass(int x, int y, int amount) {

        if (x <= 41) {
            for (i = 1; i <= amount; i += 1) {
                Print_Rectangle(x, y);
            }
        }
        else {
            error = true;
            cout << "Error - width must be below 42!\n";
        }
    };
};

int main() {
    //variable declaration/definition
    int width_Var;
    int height_Var;
    int number_of_Boxes;

    //object declaration/Body
    cout << "Enter width of rectangle/box\nWidth = ";
    cin >> width_Var;
    cout << "Enter height of rectangle/box\nHeight = ";
    cin >> height_Var;
    cout << "How many rectangles/boxes do you want?\n";
    cin >> number_of_Boxes;

    BoxClass box1(width_Var, height_Var, number_of_Boxes);

    cout <<"Box Area = "<<box1.Rectangle_Area() << endl;

//exit
    cout << "\n\n\n\n\n";
    system("pause");
    return 0;
}

带有 main.cpp、BoxClass.h、Boxclass.cpp 的新代码：

ma​​in.cpp：

#include "BoxClass.h"
#include "stdafx.h"
#include <iostream>
using namespace std;


int main() {
    //variable declaration/definition
    int width_Var;
    int height_Var;
    int number_of_Boxes;

    //object declaration/Body
    cout << "Enter width of rectangle/box\nWidth = ";
    cin >> width_Var;
    cout << "Enter height of rectangle/box\nHeight = ";
    cin >> height_Var;
    cout << "How many rectangles/boxes do you want?\n";
    cin >> number_of_Boxes;

    BoxClass box1(width_Var, height_Var, number_of_Boxes);

    cout <<"Box Area = "<<box1.Rectangle_Area() << endl;

//exit
    cout << "\n\n\n\n\n";
    system("pause");
    return 0;
}

BoxClass.h：

#ifndef BOXCLASS_H
#define BOXCLASS_H

class BoxClass {
    //prv variables
    unsigned short int width;
    int height, i;
    float space_Value;
    float height_Count = 1;
    bool error = false;

    //prv functions
    void Print_Rectangle(int x, int y);

public:
    //function shows area of individual spaces
    float Rectangle_Area();
    //function shows area of individual spaces

    // constructor
    BoxClass(int x, int y, int amount);
};

#endif

BoxClass.cpp：

#include "BoxClass.h"
#include "stdafx.h"
#include <iostream>
using namespace std;


    BoxClass::Print_Rectangle(int x, int y) {

        //calc
        space_Value = (3 * x) - 4;

        //draw top of box
        for (width = 1; width < x; width += 1) {
            cout << "...";
        }
        cout << "\n";

        //draw sides
        for (height = 1; height < y; height += 1) {
            cout << ":";
            height_Count++;
            for (width = 1; width < space_Value; width += 1) {
                cout << " ";
            }

            cout << ":\n";
        }

        //draw bottom
        cout << ":";

        for (width = 1; width < space_Value; width += 1) {
            cout << ".";
        }
        cout << ":\n";
    }


    //function shows area of individual spaces
    BoxClass::Rectangle_Area() {
        if (error == false) {
            return (height_Count - .5)*(space_Value - 1);
        }
        else {
            return 0;
        }
    }

    // constructor
    BoxClass::BoxClass(int x, int y, int amount) {

        if (x <= 41) {
            for (i = 1; i <= amount; i += 1) {
                Print_Rectangle(x, y);
            }
        }
        else {
            error = true;
            cout << "Error - width must be below 42!\n";
        }
    };

Answer 1

您忘记了类型说明符，因此您应该在 BoxClass.cpp 中更改它：

BoxClass::Print_Rectangle(int x, int y)
...
BoxClass::Rectangle_Area()

到这里：

void BoxClass::Print_Rectangle(int x, int y)
...
float BoxClass::Rectangle_Area()

还有一点题外话，我可以建议您将来使用#pragma once 代替包括警卫。

Answer 2

您需要一个构造函数，您可以在其中设置 height_Count 和 error 的值。您可能还应该定义一个析构函数，即使此时可能无事可做。这只是一个好主意。根据《Effective C++》中的 Scott Meyers，您还应该定义一个复制构造函数和一个复制赋值运算符。

这是对已发布的类型说明符建议的补充。