C++ program to demonstrate geometric operations

/*
 C/C++ code for a computer graphics program to implement a few geometric operations (sclaing, translation, rotation etc.)
 Sandipan Dey
 BCSE, JU, Kolkata
 2002
*/

#include <math.h>
#include <stdio.h>
#include <conio.h>
#include <graphics.h>
#include <dos.h>
#define SCALEFACTOR 0.5
#define MAX 3
#define PI 2.14159
#define DIR 1

void MatMult(int m,int n,int p,double a[MAX][MAX],double b[MAX][MAX],double c[MAX][MAX]) {
    for(int i=0;i<m;++i)
        for(int j=0;j<p;++j) {
            c[i][j]=0;
            for(int k=0;k<n;++k)
                c[i][j]+=a[i][k]*b[k][j];
        }
}

void Name() {
    rectangle(515,400,630,450);
    outtextxy(520,410,"SANDIPAN DEY");
    outtextxy(520,420,"BCSE-IV");
    outtextxy(520,430,"Roll-99710");
}

struct Point {
    int x,y;
};

class xyPlane {

    Point Origin;
    public:
    xyPlane() {
        Origin.x=Origin.y=0;
    }
    xyPlane(int xo,int yo) {
        Origin.x=xo;
        Origin.y=yo;
    }
    void DrawAxis() {
        int xo,yo;
        xo=Origin.x;
        yo=Origin.y;
        line(xo-300,yo,xo+300,yo);
        line(xo,yo-220,xo,yo+220);
        outtextxy(xo-10,yo+5,"O");
        outtextxy(xo+305,yo-2,"X");
        outtextxy(xo-4,yo-230,"Y");
    }
    void Line(int x1,int y1,int x2,int y2,int color=getmaxcolor()) {
        int xo,yo;
        xo=Origin.x;
        yo=Origin.y;
        setcolor(color);
        line(xo+x1,yo-y1,xo+x2,yo-y2);
        setcolor(getmaxcolor());
    }
    void Triangle(int x1,int y1,int x2,int y2,int x3,int y3,int color=getmaxcolor()) {
        Line(x1,y1,x2,y2,color);
        Line(x2,y2,x3,y3,color);
        Line(x3,y3,x1,y1,color);
    }
};

void main()
{
    clrscr();
    double I[MAX][MAX]={{0}},T1[MAX][MAX]={{0}},T2[MAX][MAX]={{0}},O[MAX][MAX]={{0}},S[MAX][MAX]={{0}},O1[MAX][MAX]={{0}};
    T1[0][0]=T1[1][1]=0;          //90 DEGREE ANTICLOCKWISE ROTATION
    T1[0][1]=1;T1[1][0]=-1;
    int ch;
    printf("\nEnter Coordinates Of The Triangle:\n");
    for(int i=0;i<3;++i) {
        printf("(X%d,Y%d): ",i+1,i+1);
        for(int j=0;j<2;++j)
            scanf("%lf",&I[i][j]);
    }
    MatMult(3,2,2,I,T1,O);
    T1[0][0]=T1[1][1]=T1[2][2]=1;
    T1[0][1]=T1[0][2]=T1[1][0]=T1[1][2]=0;
    T1[2][0]=-(O[0][0]+O[1][0]+O[2][0])/3;
    T1[2][1]=-(O[0][1]+O[1][1]+O[2][1])/3;
    S[0][0]=S[1][1]=sqrt(SCALEFACTOR);
    S[0][1]=S[0][2]=S[1][0]=S[1][2]=S[2][0]=S[2][1]=0;
    S[2][2]=1;
    MatMult(3,3,3,T1,S,T2);
    T1[2][0]=-T1[2][0];
    T1[2][1]=-T1[2][1];
    MatMult(3,3,3,T2,T1,S);
    O[0][2]=O[1][2]=O[2][2]=1;
    MatMult(3,3,3,O,S,O1);
    getch();
    int gd=DETECT,gm;
    initgraph(&gd,&gm,"");
    xyPlane pt(getmaxx()/2,getmaxy()/2);
    pt.DrawAxis();
    pt.Triangle(I[0][0],I[0][1],I[1][0],I[1][1],I[2][0],I[2][1],12);
    getch();
    pt.Triangle(O[0][0],O[0][1],O[1][0],O[1][1],O[2][0],O[2][1],9);
    Name();
    getch();
    pt.Triangle(I[0][0],I[0][1],I[1][0],I[1][1],I[2][0],I[2][1],12);
    pt.Triangle(O1[0][0],O1[0][1],O1[1][0],O1[1][1],O1[2][0],O1[2][1]);
    getch();
    cleardevice();
    pt.DrawAxis();
    pt.Triangle(I[0][0],I[0][1],I[1][0],I[1][1],I[2][0],I[2][1],14);
    for(double x=0;!kbhit();x+=PI/360)  {
        T1[0][0]=cos(x);
        T1[0][1]=DIR*sin(x);
        T1[1][0]=DIR*(-sin(x));
        T1[1][1]=cos(x);
        pt.Triangle(O[0][0],O[0][1],O[1][0],O[1][1],O[2][0],O[2][1],0);
        MatMult(3,2,2,I,T1,O);
        pt.Triangle(O[0][0],O[0][1],O[1][0],O[1][1],O[2][0],O[2][1],14);
        pt.DrawAxis();
        Name();
        delay(10);
    }
    getch();
    closegraph();
}