Robert Setiadi Web Site - Covered Area Problem (C++ version)

#include <stdio.h>
#include <conio.h>
#include <iostream.h>

int CompareLine(int a,int b,int c,int d)
{
  int pos=0;
  if (c<a)
  {
    if (d=a) pos=0; else if ((d>a) && (d<b)) pos=2; else pos=1;
  }
  else if (c==a)
  {
    if (d>=b) pos=1; else pos=2;
  }
  else if ((c>a) && (c<b)) pos=2;
  return pos;
}

int CompareTwoAreas(int x1,int y1,int x2,int y2,int x3,int y3,int x4,int y4)
{
  int dx; int dy;
  dx=CompareLine(x1,x2,x3,x4);
  dy=CompareLine(y2,y1,y4,y3);
  if ((dx==0) || (dy==0)) return 0;
    else if ((dx==1) && (dy==1)) return 1;
    else return 2;
}

class cTree
{
    char  isCovered;
    int   x1,y1,x2,y2;
    cTree * ChildArea;
  public:
    cTree(void);
    void Init(int vx1, int vy1, int vx2, int vy2);
    void AddRect(int vx1, int vy1, int vx2, int vy2);
    long CountArea();
};

cTree::cTree (void)
{
  isCovered=0;
}

void cTree::Init(int vx1, int vy1, int vx2, int vy2)
{
  x1=vx1; y1=vy1; x2=vx2; y2=vy2;
}

void cTree::AddRect(int vx1, int vy1, int vx2, int vy2)
{
  int i;
  int oldValue, newValue;
  oldValue=isCovered;
  newValue=CompareTwoAreas(x1,y1,x2,y2,vx1,vy1,vx2,vy2);
  if (newValue==1) isCovered=1;
  if ((newValue==2) && (oldValue!=1)) isCovered=2;

  if ((isCovered!=2) && (oldValue==2)) delete ChildArea;
  if (isCovered==2)
  {
    if (oldValue2)
    {
      ChildArea = new cTree[4];
      ChildArea[0].Init(x1,y1,(x1+x2)/2,(y1+y2)/2);
      ChildArea[1].Init((x1+x2)/2,y1,x2,(y1+y2)/2);
      ChildArea[2].Init(x1,(y1+y2)/2,(x1+x2)/2,y2);
      ChildArea[3].Init((x1+x2)/2,(y1+y2)/2,x2,y2);
    }
    for (i=0;i4;i++) ChildArea[i].AddRect(vx1,vy1,vx2,vy2);
  }
}

long cTree::CountArea()
{
  long temp=0;
  if (isCovered==1) temp=(x2-x1)*(y1-y2);
  if (isCovered==2) temp=ChildArea[0].CountArea()+ChildArea[1].CountArea()+
			 ChildArea[2].CountArea()+ChildArea[3].CountArea();
  return temp;
}

void main() {
  int i, NumOfRect, x1, y1, x2, y2;
  cTree WorkSpace;
  clrscr();
  WorkSpace.Init(-32768,32767,32767,-32768);
  cout  "    Covered Area Calculator -  programmed by Robert Setiadi\n";
  cout << "===============================================================\n";
  cout << "this program accept any number of rectangles as input\n";
  cout << "and calculate total area covered by all those rectangles\n";
  cout << "a rectangle is defined by top left and bottom right coordinates\n";
  cout << "accepted range from -32768 to +32767\n\n";
  cout << "Please input the number of rectangles : "; cin >> NumOfRect;
  for (i=0; i<NumOfRect; i++)
  {
    cout  "Rectangle "  i+1 << " [x1,y1,x2,y2] = ";
    scanf("%d,%d,%d,%d",&x1,&y1,&x2,&y2);
    fflush(stdin);
    WorkSpace.AddRect(x1,y1,x2,y2);
  }
  cout << "\nTotal covered area = " << WorkSpace.CountArea();
  getch();
}