我编了一个类的程序，但是编译时提示以下错误（红颜色标记的），麻烦各位看看。非常感谢：
C:\Documents and Settings\wys\桌面\c++\继承.cpp(18) :fatal error C1083: Cannot open include file: 'rectangle.h': No such file or directory
class rectangle
{
private:
    double length;
    double width;
public:
    void setdimension(double l, double w);
    double getlength() const;
    double getwidth() const;
    double area() const;
    double perimeter() const;
    void print()  const;
    rectangle();
    rectangle(double l, double w);
};

#include <iostream>
#include "rectangle.h"

using namespace std;

void rectangle::setdimension(double l, double w)
{
    if(l>0)
        length=l;
    else
        length=0;
    if(w>0)
        length=w;
    else
        length=0;
}

double rectangle::getlength() const
{
    return length;
}

double  rectangle::getwidth() const
{
    return  width;
}

double  rectangle::area() const
{
    return length*width;
}
double  rectangle::perimeter() const
{
    return  2*(length+width);
}

void rectangle::print()  const
{
    cout<<"length="<<length;
    cout<<"width="<<width;
}

rectangle::rectangle(double l, double w)
{
    setdimension(l,w);
}

rectangle::rectangle()

{
    length=0;
    width=0;
}



class boxtype:public rectangle
{
private:
    double height;
public:
    void setdimension(double l,double w,double h);
    double getheight() const;
    double area() const;
    double volume() const;
    void print() const;
    boxtype();
    boxtype(double l, double w, double h);
};


#include <iostream>
#include "boxtype.h"

using namespace std;

void boxtype::setdimension(double l, double w, double h)
{
    rectangle::setdimension(l,w);
    if(h>0)
        height=h;
    else
        height=0;
}

double boxtype::getheight() const
{
    return height;
}

double boxtype::area() const
{
    return 2*(getlength()*getwidth()+getlength()*height+getwidth()*height);
}

double boxtype::volume() const
{
    return rectangle::area()*height;
}

void boxtype::print() const
{
    rectangle::print();
    cout<<"; height="<<height;
}

boxtype::boxtype()
{
    height=0;
}

boxtype::boxtype(double l, double w, double h)
        :rectangle(l,w)
{
    if(h>0)
        height=h;
    else
        height=0;
}


#include <iostream>
#include <iomanip>
#include "rectangle.h"
#include "boxtype.h"

using namespace std;

int main()
{
    rectangle myrectangle1;
    rectangle myrectangle2(8,6);
    boxtype mybox1;
    boxtype mybox2(10,7,3);
    cout<<fixed<<showpoint<<setprecision(2);
    cout<<"line6: myrectangle1: ";
    myrectangle1.print();
    cout<<endl;
    cout<<"line 9: area of myrectangle1:"<<myrectangle1.area()<<endl;
    cout<<"line10 : myrectangle2: ";
    myrectangle2.print();
    cout<<"line 13: area of myrectangle2:"<<myrectangle2.area()<<endl;
    cout<<"line 14: mybox1:";
    mybox.print();
    cout<<endl;
    cout<<"lint 17:surface area of mybox1:";
    cout<<mybox1.area()<<endl;
    cout<<"line 18:volume of mybox1:"<<mybox1.volume()<<endl;
    cout<<"line 19: mybox2";
    mybox2.print();
    cout<<endl;
    cout<<"line 22: surface area of mybox2:"<<mybox2.area()<<endl;
    cout<<"line 24: volume of mybox2:"<<mybox2.volume()<<endl;

    return 0;
}

#ifndef RECTANGLE_H
#define RECTANGLE_H

class rectangle
{
private:
    double length;
    double width;
public:
    void setdimension(double l, double w);
    double getlength() const;
    double getwidth() const;
    double area() const;
    double perimeter() const;
    void print()  const;
    rectangle();
    rectangle(double l, double w);
};

#endif

在做一个 header file时 一定要有 红颜色标记的

其实 在你的另一个问题 已经有人说过了
https://bbs.bccn.net/thread-384716-1-1.html

有些明白了，那么类的成员函数的定义是不是要放在类的说明后面就可以了？

类的成员函数 有两种

放在类里面
class rectangle
{
private:
    double length;
    double width;
public:
    void setdimension(double l, double w){
        length = l;
        width = w;}
};

或者
放在类的说明后面

class rectangle
{
private:
    double length;
    double width;
public:
    void setdimension(double l, double w);
};

void rectangle::setdimension(double l, double w){
        length = l;
        width = w;
}

建议您多看看书！ 书比较详细

[ 本帖最后由 超级菜鸟手 于 2012-10-28 18:01 编辑 ]

是以下这样吗？我这样试一下，提示：C:\Documents and Settings\wys\桌面\c++\继承.cpp(137) : fatal error C1083: Cannot open include file: 'rectangle.h': No such file or directory
#ifndef rectangle_h  //rectangle类定义
#define rectangle_h

class rectangle
{
private:
    double length;
    double width;
public:
    void setdimension(double l, double w);
    double getlength() const;
    double getwidth() const;
    double area() const;
    double perimeter() const;
    void print()  const;
    rectangle();
    rectangle(double l, double w);
};

#endif



#ifndef boxtype_h  //boxtype类定义
#define boxtype_h
class boxtype:public rectangle
{
private:
    double height;
public:
    void setdimension(double l,double w,double h);
    double getheight() const;
    double area() const;
    double volume() const;
    void print() const;
    boxtype();
    boxtype(double l, double w, double h);
};
#endif



#include <iostream> //rectangle类成员函数定义
using namespace std;

void rectangle::setdimension(double l, double w)
{
    if(l>0)
        length=l;
    else
        length=0;
    if(w>0)
        length=w;
    else
        length=0;
}

double rectangle::getlength() const
{
    return length;
}

double  rectangle::getwidth() const
{
    return  width;
}

double  rectangle::area() const
{
    return length*width;
}
double  rectangle::perimeter() const
{
    return  2*(length+width);
}

void rectangle::print()  const
{
    cout<<"length="<<length;
    cout<<"width="<<width;
}

rectangle::rectangle(double l, double w)
{
    setdimension(l,w);
}

rectangle::rectangle()

{
    length=0;
    width=0;
}


//boxtype类成员函数定义

void boxtype::setdimension(double l, double w, double h)   
{
    rectangle::setdimension(l,w);
    if(h>0)
        height=h;
    else
        height=0;
}

double boxtype::getheight() const
{
    return height;
}

double boxtype::area() const
{
    return 2*(getlength()*getwidth()+getlength()*height+getwidth()*height);
}

double boxtype::volume() const
{
    return rectangle::area()*height;
}

void boxtype::print() const
{
    rectangle::print();
    cout<<"; height="<<height;
}

boxtype::boxtype()
{
    height=0;
}

boxtype::boxtype(double l, double w, double h)
        :rectangle(l,w)
{
    if(h>0)
        height=h;
    else
        height=0;
}

//main函数编写
#include <iostream>
#include <iomanip>
#include "rectangle.h"
#include "boxtype.h"

using namespace std;

int main()
{
    rectangle myrectangle1;
    rectangle myrectangle2(8,6);
    boxtype mybox1;
    boxtype mybox2(10,7,3);
    cout<<fixed<<showpoint<<setprecision(2);
    cout<<"line6: myrectangle1: ";
    myrectangle1.print();
    cout<<endl;
    cout<<"line 9: area of myrectangle1:"<<myrectangle1.area()<<endl;
    cout<<"line10 : myrectangle2: ";
    myrectangle2.print();
    cout<<"line 13: area of myrectangle2:"<<myrectangle2.area()<<endl;
    cout<<"line 14: mybox1:";
    mybox.print();
    cout<<endl;
    cout<<"lint 17:surface area of mybox1:";
    cout<<mybox1.area()<<endl;
    cout<<"line 18:volume of mybox1:"<<mybox1.volume()<<endl;
    cout<<"line 19: mybox2";
    mybox2.print();
    cout<<endl;
    cout<<"line 22: surface area of mybox2:"<<mybox2.area()<<endl;
    cout<<"line 24: volume of mybox2:"<<mybox2.volume()<<endl;

    return 0;
}

想问下 您的代码是 都写在一起 还是 有分.h 和.cpp 文件？

我是想在main函数中不显示类，直接调用。我给您发一个wps文档，里面是我做的详细步骤，麻烦您看看对不对。非常感谢。。

基本上你需要 3个文件


#ifndef A_H
#define A_H
class A{
//类的成员函数 };
#endif        //存为a.h 文件


#include <iostream>
#include "a.h"
using namespace std;
// 类成员函数定义   // 存为a.cpp 文件


#include <iostream>
#include "a.h"
int main(){
    ....//你的代码
} // main 文件

同仁，小弟不才。请问“//存为a.h 文件，// 存为a.cpp 文件”如何操作？是不是在新建中，输入类名后，直接在后面加上".h"或者".cpp"。。。

我按同仁的意思做了，还是提示同样的错误：C:\Documents and Settings\wys\桌面\c++\继承.cpp(137) : fatal error C1083: Cannot open include file: 'rectangle.h': No such file or directory