C Program to for Midpoint Line algorithm

#include<stdio.h>
#include<stdlib.h>
#include<graphics.h>
#include<math.h>
#include<conio.h>
#define MAX 10
 
void swap(int* a,int* b)
{
int t=*a;
*a=*b;
*b=t;
}
 
void midpointline(int x1,int y1,int x2,int y2)
{
int dx,dy,d,incry,incre,incrne,slopegt1=0;
dx=abs(x1-x2);dy=abs(y1-y2);
if(dy>dx)
{
swap(&x1,&y1);
swap(&x2,&y2);
swap(&dx,&dy);
slopegt1=1;
}
if(x1>x2)
{
swap(&x1,&x2);
swap(&y1,&y2);
}
if(y1>y2)
incry=-1;
else
incry=1;
d=2*dy-dx;
incre=2*dy;
incrne=2*(dy-dx);
while(x1<x2)
{
if(d<=0)
d+=incre;
else
{
d+=incrne;
y1+=incry;
}
x1++;
if(slopegt1)
putpixel(y1,x1,WHITE);
else
putpixel(x1,y1,WHITE);
}
}
 
void poly_line(int x[MAX],int y[MAX],int n,int thick)
{
int i=0,j=0;
for(i=0;i<n-1;i++)
for(j=0;j<thick;j++)
midpointline(x[i]+j,y[i],x[i+1]+j,y[i+1]);
}
 
int main()
{
int gd=DETECT,gm,thick;
int x[MAX],y[MAX],n,i;
printf("Number of points:");
scanf("%d",&n);
 
printf("Enter x and y co-ord:");
for(i=0;i<n;i++)
scanf("%d %d",&x[i],&y[i]);
initgraph(&gd,&gm,"..\\bgi");
if(n==1)
{
for(i=0;i<n;i++)
putpixel(x[i],y[i],YELLOW);
}
else
{
poly_line(x,y,n,1);
}
getch();
closegraph();
return 0;
}