C program to implement scaling of triangle

/* program to implement scaling of triangle

#include<stdio.h>

#include<conio.h>
#include<graphics.h>
#include<process.h>
#include<math.h>

int x1,y1,x2,y2,x3,y3,mx,my;
void draw();
void scale();
void main()
{
int gd=DETECT,gm;
int c;
initgraph(&gd,&gm,” “);
printf(“Enter the 1st point for the triangle:”);
scanf(“%d%d”,&x1,&y1);
printf(“Enter the 2nd point for the triangle:”);
scanf(“%d%d”,&x2,&y2);
printf(“Enter the 3rd point for the triangle:”);
scanf(“%d%d”,&x3,&y3);
draw();
scale();
}

void draw()
{
line(x1,y1,x2,y2);
line(x2,y2,x3,y3);
line(x3,y3,x1,y1);
}
void scale()
{
int x,y,a1,a2,a3,b1,b2,b3;
int mx,my;
printf(“Enter the scalling coordinates”);
scanf(“%d%d”,&x,&y);
mx=(x1+x2+x3)/3;
my=(y1+y2+y3)/3;
cleardevice();
a1=mx+(x1-mx)*x;
b1=my+(y1-my)*y;
a2=mx+(x2-mx)*x;
b2=my+(y2-my)*y;
a3=mx+(x3-mx)*x;
b3=my+(y3-my)*y;
line(a1,b1,a2,b2);
line(a2,b2,a3,b3);
line(a3,b3,a1,b1);
draw();
getch();
}