Thread: Can someone help me with classes please? :)

I want to make two classes and there are variables that need to be used in both classes. How do I create variables that can be accessible by both of the classes? Thanks!

Inheritance? Friend function? Nested class? Friend class? It all depends.

Here are some examples:

Code:

class first{
private:
int a;
protected:
int b;
public:
int c;
};

class second : public first{
private:
// none
protected:
// b is here
public:
// c is here
};

Hope that made sense, I think I did it right.

Well, ok, I'm trying to make this "Snake" game. I have a FruitClass and I have a SnakeClass. But there are these two vectors that I need to use in both classes. The vectors are declared in the public part of the Snake Class. How can I use those vectors in the FruitClass? btw, cheesymoo, I tried that it didn't work

Oh wait, after I moved the fruit class underneath the snake class and added the public SnakeClass thing, I can compile it now, but the snake does not move O.O

EDIT: It moves now, nevermind ^.^;; Thanks so much everyone!!

It moves now, but the vectors don't seem to change in the FruitClass. If you put the public SnakeClass thing into the FruitClass, do the vectors accessed from FruitClass change as they are changed in SnakeClass?

Yup, I just confirmed that by "cout"ing the coordinates of the snake head in the FruitClass, they do not change at all even though the snake is moving. O.O

ya.... I seem like I'm missing something... How do you specify it? ^_^

this is my entire game ^_^;;

Code:

#include <iostream.h>
#include <stdlib.h>
#include <utility.h>
#include <conio.h>
#include <lvp\vector.h>


const char KB_ARROWUP='i';
const char KB_ARROWLEFT='j';
const char KB_ARROWRIGHT='l';
const char KB_ARROWDOWN='k';

class SnakeClass
{
    public:
      SnakeClass();
      ~SnakeClass();
      void Initializer();
      void EraseSnake();
      void DisplaySnake();
      void CheckMove();
      void MoveSnake();
      void SnakeDirection();
      void Delay();
      bool CheckCrash();
      vector<int> SnakeX;
      vector<int> SnakeY;

    private:
      bool bCrash;
      char cKeyPressed, cTemp;
      int iXerase, iYerase;
};

//Default Constructor
SnakeClass::SnakeClass()
{
      SnakeX.resize(4);
      SnakeY.resize(4);
      bCrash=false;
      cKeyPressed=' ';
      cTemp=' ';
}

//Deconstructor
SnakeClass::~SnakeClass()
{
}

//Initializes the game
void SnakeClass::Initializer()
{
      //Draws the box
      for(int iSides=10; iSides<=40; iSides++)  // Leftwall 20 Rightwall 60
      {
         gotoxy(20, iSides);
         cout<<"#";
         gotoxy(60, iSides);
         cout<<"#";
      }
      for(int iTopBot=21; iTopBot<=59; iTopBot++)  // Topwall 10 Botwall 40
      {
         gotoxy(iTopBot, 10);
         cout<<"#";
         gotoxy(iTopBot, 40);
         cout<<"#";
      }

      // Initialize snake values
      for (int iIndex=0; iIndex<4; iIndex++)
      {
         SnakeX[iIndex]=iIndex+40;
         SnakeY[iIndex]=25;
      }
}

//Erase snake as it moves
void SnakeClass::EraseSnake()
{
         gotoxy(iXerase, iYerase);
         cout << " ";
         iXerase=SnakeX[SnakeX.length()-1];
         iYerase=SnakeY[SnakeY.length()-1];
}

//Draw a snake on the screen
void SnakeClass::DisplaySnake()
{
         //Display Snake
         for(int iIndex=0; iIndex<SnakeX.length(); iIndex++)
         {
            gotoxy(SnakeX[iIndex], SnakeY[iIndex]);
            cout << "o";

         }
}

void SnakeClass::CheckMove()
{
         // Check for player move
         if(kbhit())
         {
            cTemp=getch();
            if(cTemp==KB_ARROWUP || cTemp==KB_ARROWLEFT || cTemp==KB_ARROWRIGHT || cTemp==KB_ARROWDOWN)
               cKeyPressed=cTemp;
         }
}

void SnakeClass::MoveSnake()
{
         if (cKeyPressed!=' ')
         {
            //Move snake body pieces
            for(int iIndex=SnakeX.length()-1; iIndex>0; iIndex--)
            {
                 SnakeX[iIndex]=SnakeX[iIndex-1];
                 SnakeY[iIndex]=SnakeY[iIndex-1];
            }
         }

}

void SnakeClass::SnakeDirection()
{
      //Set continuous direction for snake
      if (cKeyPressed!=' ')
      {
         if(cKeyPressed==KB_ARROWUP)
            SnakeY[0]--;
         else if(cKeyPressed==KB_ARROWLEFT)
            SnakeX[0]--;
         else if(cKeyPressed==KB_ARROWRIGHT)
            SnakeX[0]++;
         else if(cKeyPressed==KB_ARROWDOWN)
            SnakeY[0]++;
         else;
      }
}

//Checks if the snake crashed
bool SnakeClass::CheckCrash()
{
      if(SnakeX[0]==20 || SnakeX[0]==60)
         bCrash=true;
      else if (SnakeY[0]==10 || SnakeY[0]==40)
         bCrash=true;
      else;

      for (int iCounter=1; iCounter<SnakeX.length(); iCounter++)
      {
          if (SnakeX[0]==SnakeX[iCounter]&&SnakeY[0]==SnakeY[iCounter])
          {
               bCrash=true;
          }
      }
      return(bCrash);

}

//Slows down the snake
void SnakeClass::Delay()
{
      //Delay and erase code
      Sleep(200);

}

class FruitClass : public SnakeClass
{
    public:
      FruitClass();
      ~FruitClass();
      void Initializer();
      void GenerateFruit();
      void CheckFruit();
      int iScore;

   private:
      int iXFruit, iYFruit;
      bool bFruit;

};


//Default Constructor
FruitClass::FruitClass()
{
      randomize();
      iXFruit=random(39)+21;
      iYFruit=random(29)+11;
      iScore=0;
      bFruit=true;
}

//Deconstructor
FruitClass::~FruitClass()
{
}

//Initializes the game
void FruitClass::Initializer()
{
      iXFruit=random(39)+21;
      iYFruit=random(29)+11;
      bFruit=true;
}

//Generate Fruits
void FruitClass::GenerateFruit()
{
         //if there is no fruit, generate one
         if(bFruit==false)
         {
            iXFruit=21+(random(39));
            iYFruit=11+(random(29));
            bFruit=true;
         }
         //if there is a fruit, draw it on the screen
         else if(bFruit==true)
         {
            gotoxy(iXFruit, iYFruit);
            cout << "*";
         }
}

//Check if fruit is where the snake head is
void FruitClass::CheckFruit()
{
         gotoxy(1,1);
         cout<<SnakeX[0]<<" "<<SnakeY[0]<<endl;
         cout<<iXFruit<<" "<<iYFruit;
         if(SnakeX[0]== iXFruit && SnakeY[0]==iYFruit)
         {
            iScore+=10;
            SnakeX.resize(SnakeX.length()+1);
            SnakeY.resize(SnakeY.length()+1);
            bFruit=false;
         }
}

int main()
{
      bool bCrash;
      int iScore;
      bool bFruit;
      SnakeClass Snake;
      FruitClass Fruit;

      Snake.Initializer();
      Fruit.Initializer();
      Snake.DisplaySnake();
      // Start of game tick
      do
      {
         Snake.CheckMove();

         Fruit.GenerateFruit();

         Fruit.CheckFruit();

         Snake.EraseSnake();

         Snake.MoveSnake();

         Snake.DisplaySnake();

         Snake.SnakeDirection();

         bCrash=Snake.CheckCrash();

         Snake.Delay();

         gotoxy(20,9);
         cout<<"Score: "<<Fruit.iScore;

      }
      while(!bCrash);
      gotoxy(38, 25);
      cout << "CRASH!!";

      gotoxy(1, 49);
      system("PAUSE");
      return (0);
}