在C+中定义类的问题+； 我对C++编程很陌生，但有java编程的背景。我正在尝试使用.cpp和.h文件创建一个类，以便它们可以包含在任何项目中。在实现下面的代码之后，我收到了多个错误，例如“使用未定义的类型‘SUN’”和“zsizei:undeclared identifier”。据我所知，我在实现中完全遵循了各种教程和参考资料，但我确信我的代码中存在错误，否则我不会有任何问题

这是孙先生

#ifndef SUN_H
#define SUN_H

class Sun {
public:
    void init(float xsize, float ysize, float zsize);
    void draw();
private:
    float xsizei; //size of interior
    float ysizei; //size of interior
    float zsizei; //size of interior

    float xsizee; //size of exterior
    float ysizee; //size of exterior
    float zsizee; //size of exterior

    float xySlices;
    float yzSlices;
    float thetaXY;
    float thetaYZ;

        float ratio;
    };

#endif

这里是sun.cpp：

#ifdef _APPLE_
#  include <GL/glew.h>
#  include <GL/freeglut.h>
#  include <OpenGL/glext.h>
#else
#  include <GL/glew.h>
#  include <GL/freeglut.h>
//#  include <GL/glext.h>
#pragma comment(lib, "glew32.lib") 
#endif

# include <math.h>
# include "sun.h"

# define PI 3.141569

class Sun {
public:
    void init(float xsize, float ysize, float zsize);
    void draw();
private:
    float xsizei; //size of interior
    float ysizei; //size of interior
    float zsizei; //size of interior

    float xsizee; //size of exterior
    float ysizee; //size of exterior
    float zsizee; //size of exterior

    float xySlices = 36;
    float yzSlices = 36;
    float thetaXY = xySlices / (2 * PI);
    float thetaYZ = yzSlices / (2 * PI);

    float ratio = 0.8;
};

/**
* Object will be drawn with its origin in its center
*/
void Sun::init(float xs, float ys, float zs) {
    xsizei = xs * ratio;
    ysizei = ys * ratio;
    zsizei = zs * ratio;

    xsizee = xs * (1 - ratio);
    ysizee = ys * (1 - ratio);
    zsizee = zs * (1 - ratio);
}

/*
* Draw this object
*/
void Sun::draw() {
    //first, draw the ball part
    for (int i = 0; i < xySlices; i++) {

        float yStart = ysizei / 2 * sin(thetaYZ * i);
        float yEnd = ysizei / 2 * sin(thetaYZ * (i + 1));

        float zStart = zsizei / 2 * sin(thetaYZ * i);
        float zEnd = zsizei / 2 * sin(thetaYZ * (i + 1));

        for (int j = 0; j < yzSlices; j++) {
            float xStart = xsizei / 2 * cos(thetaXY * j);
            float xEnd = xsizei / 2 * cos(thetaXY * (j + 1));

            glVertex3f(xStart, yStart, zStart);
            glVertex3f(xStart, yEnd, zEnd);
            glVertex3f(xEnd, yEnd, zEnd);

            glVertex3f(xEnd, yEnd, zEnd);
            glVertex3f(xEnd, yStart, zStart);
            glVertex3f(xStart, yStart, zStart);
        }

    }
}

---

您正在cpp中声明Sun类#包括复制和粘贴头文件。因此，您正在创建两个具有相同类名的声明，而编译器不知道选择哪一个。从cpp中删除类声明，它应该可以工作。

问题是.cpp文件正在重新声明sun类。相反，您需要从.cpp中删除类Sun

要实现.h/.cpp格式，请执行以下操作：

In.h

In.cpp

#include "sun.h"

//define the function no need to write class sun again
void foo(int s) {
x = s;
}

---

C++就像一支枪——你不会通过尝试和错误来学习它。阅读这本好书：请显示实际的错误信息。我假设你在某个地方有一个main。请显示codeAfter

#include“sun.h”

您在.cpp文件中已经有了类声明。你不应该重复。与java不同，C++中通常将声明和函数定义分隔成两个单独的文件。不同的语言！您不需要复制

类Sun{…}

在sun.cpp中，include“sun.h”就是这样做的

#ifndef SUN_H
#define SUN_H
class Sun { 
int x;
public : 
    void foo(int);
}
#endif

#include "sun.h"

//define the function no need to write class sun again
void foo(int s) {
x = s;
}