[英]Problems Defining Class in C++
我是C ++编程的新手,但是具有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。 在执行以下代码后,我收到多个错误,例如“使用未定义类型'SUN'”和'zsizei:未声明的标识符'。 据我所知,我在实现过程中完全遵循了各种教程和参考,但是我确信代码中有错误,否则我不会有任何问题。
这是sun.h:
#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);
}
}
}
我以为我可能会重复声明,所以我尝试省略了已经声明的sun.cpp中的内容,但这不能解决问题。
这是我收到的错误消息:
Severity Code Description Project File Line Suppression State
Error C2065 'ratio': undeclared identifier Proj c:\\sun.cpp 48
Error C2027 use of undefined type 'Sun' Proj c:\\sun.cpp 41
Error C2027 use of undefined type 'Sun' Proj c:\\sun.cpp 54
Error C2065 'zsizei': undeclared identifier Proj c:\\sun.cpp 44
Error C2065 'zsizei': undeclared identifier Proj c:\\sun.cpp 61
Error C2065 'zsizei': undeclared identifier Proj c:\\sun.cpp 62
Error C2065 'zsizee': undeclared identifier Proj c:\\sun.cpp 48
Error C2065 'yzSlices': undeclared identifier Proj c:\\sun.cpp 64
Error C2065 'ysizei': undeclared identifier Proj c:\\sun.cpp 43
Error C2065 'ysizei': undeclared identifier Proj c:\\sun.cpp 58
Error C2065 'ysizei': undeclared identifier Proj c:\\sun.cpp 59
Error C2065 'ysizee': undeclared identifier Proj c:\\sun.cpp 47
Error C2065 'xySlices': undeclared identifier Proj c:\\sun.cpp 56
Error C2065 'xsizei': undeclared identifier Proj c:\\sun.cpp 42
Error C2065 'xsizei': undeclared identifier Proj c:\\s...
您正在cpp中重新声明Sun类。 #include本质上复制并粘贴了头文件。 因此,您要创建两个具有相同类名的声明,并且编译器不知道该选择哪个。 从cpp中删除类声明,它应该可以工作。
问题是您的.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:
在.h中
#ifndef SUN_H
#define SUN_H
class Sun {
int x;
public :
void foo(int);
}
#endif
在.cpp中
#include "sun.h"
//define the function no need to write class sun again
void foo(int s) {
x = s;
}
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