Programming Forums > Application Development > C++

The Dark · Oct 27th, 2006, 2:05 AM

What error?
You need to post the actual error that the compiler gives you and also post your current code.

brad sue · Oct 27th, 2006, 2:10 AM

the compiler error is:

In member function `void Rectangle::draw(Screen&)': 
`char Screen::pixels[20][30]' is private

I dont know how to get rid of it. I cannot make my pixels public member:It is imposed
here is the actual code:

(Toggle Plain Text)

class Rectangle;
    // class screen
   class Screen
   {
         private:
                 char pixels[20][30];
         public:
                //friend class Rectangle; 
                Screen(void);
                ~Screen(void);
                void setPoint(const Point&,char);
                void draw(void);
   };

// implementation of screen class

   Screen::Screen()
   {
         int i,j;
         for(i=0;i<20;i++){
             for(j=0;j<30;j++){
                 pixels[i][j]='.';}}
   }             
      
   Screen::~Screen(){}
   
   void Screen::setPoint(const Point & object, char c)
   {
        int i=object.getX();
        int j=object.getY();
        
        pixels[i][j]=c;
   }          
                 
   void Screen::draw()
   {
        for( int i=0;i<20;i++)
            {for( int j=0;j<30;j++)
                 {cout<<pixels[i][j];}
                 cout<<endl;
                 }
   }           
    
    
    class Rectangle{
         
          private:
                  int height;
                  int width;
                  Point upLeft;// upper left corner of a rectangle
                  char Paint;
          public:
                 friend class Screen;
                 Rectangle(void);
                 Rectangle(const Point&,int,int,char);
                 ~Rectangle();
                 void set(const Point&,int,int,char);//set values of existing rectangle
                 void setPaint(char);
                 void setPoint(const Point&);//sets upper left corner of rectangle
                 void setPoint(int, int);//sets upper left corner of rectangle
                 void setSize(int,int);//sets height and width
                 int getX(void)const;//Return upp left corners' x coordinate
                 int getY(void)const;//Return upp left corners' y coordinate
                 int getWidth(void)const;
                 int getHeight(void)const;
                 char getPaint(void)const;
                 void draw(Screen&);//prints contents of rectangle on screen
};
   // implementation class Rectangle
   
   Rectangle::Rectangle()
   {
          height=1;
          width=1;
          Paint='*';
   }
   Rectangle::~Rectangle()
{
}
   
  //paramerized constructor
   /*Rectangle::Rectangle(const Point& object,int h,int w,char c) : set(object, h, w, c) {}*/
   Rectangle::Rectangle(const Point& object,int h,int w,char c) : upLeft(object),height(h),width(w),Paint(c){}
   
   
   void Rectangle::set(const Point& object,int h,int w,char c)
   {
          
        upLeft=object;  
        height=h;
        width=w;
        Paint=c;
   }
   
   void Rectangle::setPaint(char e)
   {  
        Paint=e;
   }
   
   void Rectangle::setPoint(const Point& object)
   {  
        upLeft=object;
   }
   
    
     void Rectangle::setPoint(int x,int y)
   {  
       upLeft.setPoint(x,y);
   }
    
    
     int Rectangle::getX()const// to check
     {
         upLeft.getX();
     }
             
     int Rectangle::getY()const
     {
         upLeft.getY();
     }                


     int Rectangle::getWidth()const
     {
         return width;
     }
     
     int Rectangle::getHeight()const
     {
         return height;
     }
     
     char Rectangle::getPaint()const
     {
          return Paint;
     }
     
          
          
     void Rectangle::draw( Screen&  object//prints contents of rectangle on screen object
     {
          
          int x1=upLeft.getX();
          int y1=upLeft.getY();
          for(int i=x1;i<(x1+width);i++)
             for(int j=y1;j<(y1+height);j++)
                 object.pixels[x1][y1]; // you said it does not make sense
                
      }

class Rectangle;
    // class screen
   class Screen
   {
         private:
                 char pixels[20][30];
         public:
                //friend class Rectangle; 
                Screen(void);
                ~Screen(void);
                void setPoint(const Point&,char);
                void draw(void);
   };

// implementation of screen class

   Screen::Screen()
   {
         int i,j;
         for(i=0;i<20;i++){
             for(j=0;j<30;j++){
                 pixels[i][j]='.';}}
   }             
      
   Screen::~Screen(){}
   
   void Screen::setPoint(const Point & object, char c)
   {
        int i=object.getX();
        int j=object.getY();
        
        pixels[i][j]=c;
   }          
                 
   void Screen::draw()
   {
        for( int i=0;i<20;i++)
            {for( int j=0;j<30;j++)
                 {cout<<pixels[i][j];}
                 cout<<endl;
                 }
   }           
    
    
    class Rectangle{
         
          private:
                  int height;
                  int width;
                  Point upLeft;// upper left corner of a rectangle
                  char Paint;
          public:
                 friend class Screen;
                 Rectangle(void);
                 Rectangle(const Point&,int,int,char);
                 ~Rectangle();
                 void set(const Point&,int,int,char);//set values of existing rectangle
                 void setPaint(char);
                 void setPoint(const Point&);//sets upper left corner of rectangle
                 void setPoint(int, int);//sets upper left corner of rectangle
                 void setSize(int,int);//sets height and width
                 int getX(void)const;//Return upp left corners' x coordinate
                 int getY(void)const;//Return upp left corners' y coordinate
                 int getWidth(void)const;
                 int getHeight(void)const;
                 char getPaint(void)const;
                 void draw(Screen&);//prints contents of rectangle on screen
};
   // implementation class Rectangle
   
   Rectangle::Rectangle()
   {
          height=1;
          width=1;
          Paint='*';
   }
   Rectangle::~Rectangle()
{
}
   
  //paramerized constructor
   /*Rectangle::Rectangle(const Point& object,int h,int w,char c) : set(object, h, w, c) {}*/
   Rectangle::Rectangle(const Point& object,int h,int w,char c) : upLeft(object),height(h),width(w),Paint(c){}
   
   
   void Rectangle::set(const Point& object,int h,int w,char c)
   {
          
        upLeft=object;  
        height=h;
        width=w;
        Paint=c;
   }
   
   void Rectangle::setPaint(char e)
   {  
        Paint=e;
   }
   
   void Rectangle::setPoint(const Point& object)
   {  
        upLeft=object;
   }
   
    
     void Rectangle::setPoint(int x,int y)
   {  
       upLeft.setPoint(x,y);
   }
    
    
     int Rectangle::getX()const// to check
     {
         upLeft.getX();
     }
             
     int Rectangle::getY()const
     {
         upLeft.getY();
     }                


     int Rectangle::getWidth()const
     {
         return width;
     }
     
     int Rectangle::getHeight()const
     {
         return height;
     }
     
     char Rectangle::getPaint()const
     {
          return Paint;
     }
     
          
          
     void Rectangle::draw( Screen&  object//prints contents of rectangle on screen object
     {
          
          int x1=upLeft.getX();
          int y1=upLeft.getY();
          for(int i=x1;i<(x1+width);i++)
             for(int j=y1;j<(y1+height);j++)
                 object.pixels[x1][y1]; // you said it does not make sense
                
      }

The Dark · Oct 27th, 2006, 2:17 AM

Oh well, if you edit your post, I'll edit mine.

You still have this in class Screen

(Toggle Plain Text)

//friend class Rectangle;

This need to be uncommented, it doesn't do anything while commented out.

With this code in Rectangle:draw:

(Toggle Plain Text)

                 object.pixels[x1][y1]; // you said it does not make sense

What do you want this line to do? It is not assigning anything, and it is not testing anything. I assume you want something like:

(Toggle Plain Text)

                 object.pixels[x1][y1] = 'x';

brad sue · Oct 27th, 2006, 2:25 AM

I am sorry for the misunderstanding. I made all the changes you suggested me in my last post. Now the only problem is the one I just posted above.

The Dark · Oct 27th, 2006, 2:33 AM

See my edit to my previous post.

You might find it better all round to use the Screen's public setPoint function, rather than mucking about making things friends. Then you just make Rectangle::draw something like:

(Toggle Plain Text)

     void Rectangle::draw( Screen&  object)//prints contents of rectangle on screen object
     {
          
          int x1=upLeft.getX();
          int y1=upLeft.getY();
          for(int i=x1;i<(x1+width);i++)
             for(int j=y1;j<(y1+height);j++)
             {
                 Point point(x1,y1);
                 object.setPoint(point, 'x');
             }                
      }

If you are doing this for a class, then I would imagine that is what they would want you to do.

brad sue · Oct 27th, 2006, 2:39 AM

In the program, we have 2 draw function one in Rectangle and one inScreen.

We are are looking at the drwas in rectngle. It is supposed to "print the content ot the rectangle on the screen object"
The way I understand, I need to store the rectangle (filled with Paint)
in the pixels[x][y];

And the function draw in Screen will print the rectangle on the monitor.

after storing the rectangle the Sreen::draw() should display something like:

AAAAAAA
AAAAAAA
AAAAAAA
AAAAAAA

if 'A' is the paint of the rectangle.

The Dark · Oct 27th, 2006, 2:48 AM

Yes, thats the way it looks like it should work.
I think the setPoint function in Screen is the way the Rectangle::draw function should be changing the Screen object's "pixels" array values. See the previous post for the code (replace 'x' with paint)

brad sue · Oct 27th, 2006, 2:49 AM

It compiles well (with Paint included). Now I need to see if it does what I need.
I will log out now I get some sleep.
Thank you indeed Dark.

The Dark · Oct 27th, 2006, 2:50 AM

Edit - oops pressed the save button twice.

Good job, hope it works for you.

brad sue · Oct 27th, 2006, 5:39 PM

HI, I tested the functions with the following main:

(Toggle Plain Text)

int main()
{
    Screen ecran;
    Point p1(2,4);
    Rectangle rect0(p1,3,7,0);
    
    Point p2(7,7);
    Rectangle rect1(p2,3,7,1);
   
    Point p3(12,3);
    Rectangle rect3(p3,3,24,3);
    
    Point p4(2,18);
    Rectangle rect4(p4,16,5,4);
    
    rect0.draw(ecran);
    rect1.draw(ecran);
    rect3.draw(ecran);
    rect4.draw(ecran);

    ecran.draw();

    cin.get();
    return 0;
}

On the output, the program does not display the rectanles, but
marks the starting point (upper left corner) with totally random characters ( like heart or blank, diamond...)
It does not get the paint character.

the output should be like overlapped rectangle filled with numbers.
The function Rectangle::draw() seems fine to me.
Can you see what is wrong?

Oct 27th, 2006, 2:10 AM	#12
brad sue Hobbyist Programmer Join Date: Mar 2006 Posts: 115 Rep Power: 3	the compiler error is: (Toggle Plain Text) In member function `void Rectangle::draw(Screen&)': `char Screen::pixels[20][30]' is private In member function `void Rectangle::draw(Screen&)': `char Screen::pixels[20][30]' is private I dont know how to get rid of it. I cannot make my pixels public member:It is imposed here is the actual code: (Toggle Plain Text) class Rectangle; // class screen class Screen { private: char pixels[20][30]; public: //friend class Rectangle; Screen(void); ~Screen(void); void setPoint(const Point&,char); void draw(void); }; // implementation of screen class Screen::Screen() { int i,j; for(i=0;i<20;i++){ for(j=0;j<30;j++){ pixels[i][j]='.';}} } Screen::~Screen(){} void Screen::setPoint(const Point & object, char c) { int i=object.getX(); int j=object.getY(); pixels[i][j]=c; } void Screen::draw() { for( int i=0;i<20;i++) {for( int j=0;j<30;j++) {cout<<pixels[i][j];} cout<<endl; } } class Rectangle{ private: int height; int width; Point upLeft;// upper left corner of a rectangle char Paint; public: friend class Screen; Rectangle(void); Rectangle(const Point&,int,int,char); ~Rectangle(); void set(const Point&,int,int,char);//set values of existing rectangle void setPaint(char); void setPoint(const Point&);//sets upper left corner of rectangle void setPoint(int, int);//sets upper left corner of rectangle void setSize(int,int);//sets height and width int getX(void)const;//Return upp left corners' x coordinate int getY(void)const;//Return upp left corners' y coordinate int getWidth(void)const; int getHeight(void)const; char getPaint(void)const; void draw(Screen&);//prints contents of rectangle on screen }; // implementation class Rectangle Rectangle::Rectangle() { height=1; width=1; Paint=''; } Rectangle::~Rectangle() { } //paramerized constructor /Rectangle::Rectangle(const Point& object,int h,int w,char c) : set(object, h, w, c) {}/ Rectangle::Rectangle(const Point& object,int h,int w,char c) : upLeft(object),height(h),width(w),Paint(c){} void Rectangle::set(const Point& object,int h,int w,char c) { upLeft=object; height=h; width=w; Paint=c; } void Rectangle::setPaint(char e) { Paint=e; } void Rectangle::setPoint(const Point& object) { upLeft=object; } void Rectangle::setPoint(int x,int y) { upLeft.setPoint(x,y); } int Rectangle::getX()const// to check { upLeft.getX(); } int Rectangle::getY()const { upLeft.getY(); } int Rectangle::getWidth()const { return width; } int Rectangle::getHeight()const { return height; } char Rectangle::getPaint()const { return Paint; } void Rectangle::draw( Screen& object//prints contents of rectangle on screen object { int x1=upLeft.getX(); int y1=upLeft.getY(); for(int i=x1;i<(x1+width);i++) for(int j=y1;j<(y1+height);j++) object.pixels[x1][y1]; // you said it does not make sense } class Rectangle; // class screen class Screen { private: char pixels[20][30]; public: //friend class Rectangle; Screen(void); ~Screen(void); void setPoint(const Point&,char); void draw(void); }; // implementation of screen class Screen::Screen() { int i,j; for(i=0;i<20;i++){ for(j=0;j<30;j++){ pixels[i][j]='.';}} } Screen::~Screen(){} void Screen::setPoint(const Point & object, char c) { int i=object.getX(); int j=object.getY(); pixels[i][j]=c; } void Screen::draw() { for( int i=0;i<20;i++) {for( int j=0;j<30;j++) {cout<<pixels[i][j];} cout<<endl; } } class Rectangle{ private: int height; int width; Point upLeft;// upper left corner of a rectangle char Paint; public: friend class Screen; Rectangle(void); Rectangle(const Point&,int,int,char); ~Rectangle(); void set(const Point&,int,int,char);//set values of existing rectangle void setPaint(char); void setPoint(const Point&);//sets upper left corner of rectangle void setPoint(int, int);//sets upper left corner of rectangle void setSize(int,int);//sets height and width int getX(void)const;//Return upp left corners' x coordinate int getY(void)const;//Return upp left corners' y coordinate int getWidth(void)const; int getHeight(void)const; char getPaint(void)const; void draw(Screen&);//prints contents of rectangle on screen }; // implementation class Rectangle Rectangle::Rectangle() { height=1; width=1; Paint=''; } Rectangle::~Rectangle() { } //paramerized constructor /Rectangle::Rectangle(const Point& object,int h,int w,char c) : set(object, h, w, c) {}/ Rectangle::Rectangle(const Point& object,int h,int w,char c) : upLeft(object),height(h),width(w),Paint(c){} void Rectangle::set(const Point& object,int h,int w,char c) { upLeft=object; height=h; width=w; Paint=c; } void Rectangle::setPaint(char e) { Paint=e; } void Rectangle::setPoint(const Point& object) { upLeft=object; } void Rectangle::setPoint(int x,int y) { upLeft.setPoint(x,y); } int Rectangle::getX()const// to check { upLeft.getX(); } int Rectangle::getY()const { upLeft.getY(); } int Rectangle::getWidth()const { return width; } int Rectangle::getHeight()const { return height; } char Rectangle::getPaint()const { return Paint; } void Rectangle::draw( Screen& object//prints contents of rectangle on screen object { int x1=upLeft.getX(); int y1=upLeft.getY(); for(int i=x1;i<(x1+width);i++) for(int j=y1;j<(y1+height);j++) object.pixels[x1][y1]; // you said it does not make sense } Last edited by brad sue; Oct 27th, 2006 at 2:21 AM.

Oct 27th, 2006, 2:17 AM	#13
The Dark Expert Programmer Join Date: Jun 2005 Posts: 810 Rep Power: 4	Oh well, if you edit your post, I'll edit mine. You still have this in class Screen (Toggle Plain Text) //friend class Rectangle; //friend class Rectangle; This need to be uncommented, it doesn't do anything while commented out. With this code in Rectangle:draw: (Toggle Plain Text) object.pixels[x1][y1]; // you said it does not make sense object.pixels[x1][y1]; // you said it does not make sense What do you want this line to do? It is not assigning anything, and it is not testing anything. I assume you want something like: (Toggle Plain Text) object.pixels[x1][y1] = 'x'; object.pixels[x1][y1] = 'x'; Last edited by The Dark; Oct 27th, 2006 at 2:29 AM. Reason: Parent Post Changed

Oct 27th, 2006, 2:33 AM	#15
The Dark Expert Programmer Join Date: Jun 2005 Posts: 810 Rep Power: 4	See my edit to my previous post. You might find it better all round to use the Screen's public setPoint function, rather than mucking about making things friends. Then you just make Rectangle::draw something like: (Toggle Plain Text) void Rectangle::draw( Screen& object)//prints contents of rectangle on screen object { int x1=upLeft.getX(); int y1=upLeft.getY(); for(int i=x1;i<(x1+width);i++) for(int j=y1;j<(y1+height);j++) { Point point(x1,y1); object.setPoint(point, 'x'); } } void Rectangle::draw( Screen& object)//prints contents of rectangle on screen object { int x1=upLeft.getX(); int y1=upLeft.getY(); for(int i=x1;i<(x1+width);i++) for(int j=y1;j<(y1+height);j++) { Point point(x1,y1); object.setPoint(point, 'x'); } } If you are doing this for a class, then I would imagine that is what they would want you to do.

Oct 27th, 2006, 5:39 PM	#20
brad sue Hobbyist Programmer Join Date: Mar 2006 Posts: 115 Rep Power: 3	HI, I tested the functions with the following main: (Toggle Plain Text) int main() { Screen ecran; Point p1(2,4); Rectangle rect0(p1,3,7,0); Point p2(7,7); Rectangle rect1(p2,3,7,1); Point p3(12,3); Rectangle rect3(p3,3,24,3); Point p4(2,18); Rectangle rect4(p4,16,5,4); rect0.draw(ecran); rect1.draw(ecran); rect3.draw(ecran); rect4.draw(ecran); ecran.draw(); cin.get(); return 0; } int main() { Screen ecran; Point p1(2,4); Rectangle rect0(p1,3,7,0); Point p2(7,7); Rectangle rect1(p2,3,7,1); Point p3(12,3); Rectangle rect3(p3,3,24,3); Point p4(2,18); Rectangle rect4(p4,16,5,4); rect0.draw(ecran); rect1.draw(ecran); rect3.draw(ecran); rect4.draw(ecran); ecran.draw(); cin.get(); return 0; } On the output, the program does not display the rectanles, but marks the starting point (upper left corner) with totally random characters ( like heart or blank, diamond...) It does not get the paint character. the output should be like overlapped rectangle filled with numbers. The function Rectangle::draw() seems fine to me. Can you see what is wrong?

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Oct 27th, 2006, 2:05 AM	#11
The Dark Expert Programmer Join Date: Jun 2005 Posts: 810 Rep Power: 4	What error? You need to post the actual error that the compiler gives you and also post your current code.

Oct 27th, 2006, 2:25 AM	#14
brad sue Hobbyist Programmer Join Date: Mar 2006 Posts: 115 Rep Power: 3	I am sorry for the misunderstanding. I made all the changes you suggested me in my last post. Now the only problem is the one I just posted above.

Oct 27th, 2006, 2:39 AM	#16
brad sue Hobbyist Programmer Join Date: Mar 2006 Posts: 115 Rep Power: 3	In the program, we have 2 draw function one in Rectangle and one inScreen. We are are looking at the drwas in rectngle. It is supposed to "print the content ot the rectangle on the screen object" The way I understand, I need to store the rectangle (filled with Paint) in the pixels[x][y]; And the function draw in Screen will print the rectangle on the monitor. after storing the rectangle the Sreen::draw() should display something like: AAAAAAA AAAAAAA AAAAAAA AAAAAAA if 'A' is the paint of the rectangle.

Oct 27th, 2006, 2:48 AM	#17
The Dark Expert Programmer Join Date: Jun 2005 Posts: 810 Rep Power: 4	Yes, thats the way it looks like it should work. I think the setPoint function in Screen is the way the Rectangle::draw function should be changing the Screen object's "pixels" array values. See the previous post for the code (replace 'x' with paint)

Oct 27th, 2006, 2:49 AM	#18
brad sue Hobbyist Programmer Join Date: Mar 2006 Posts: 115 Rep Power: 3	It compiles well (with Paint included). Now I need to see if it does what I need. I will log out now I get some sleep. Thank you indeed Dark.

Oct 27th, 2006, 2:50 AM	#19
The Dark Expert Programmer Join Date: Jun 2005 Posts: 810 Rep Power: 4	Edit - oops pressed the save button twice. Good job, hope it works for you.

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