DDA Line Drawing Algorithm

#include<stdio.h>
#include<conio.h>
#include<graphics.h>
void DDA(int x1,int y1,int x2,int y2,int col,int del);
void main()
{
int gd=DETECT,gm,x1,x2,y1,y2;
initgraph(&gd,&gm,"");
printf("Enter (x1,y1) and (x2,y2) : ");
scanf("%d%d%d%d",&x1,&y1,&x2,&y2);
DDA(x1,y1,x2,y2,14,20);
getch();
closegraph();
}
void DDA(int x1,int y1,int x2,int y2,int col,int del)
{
int dx,dy,s,i,xi,yi,x,y;
x=x1,y=y1;
dx=x2-x1;
dy=y2-y1;
if(dx>dy)
s=dx;
else
s=dy;
xi=dx/s;
yi=dy/s;
putpixel(x,y,col);
for(i=0;i<s;i++)
{
x+=xi;
y+=yi;
putpixel(x,y,col);
delay(del);
}
}