Draw a line using DDA line drawing algorithm

Program: Draw a line using DDA line drawing algorithm
#include<stdio.h>
#include<graphics.h>
#include<conio.h>
#include<math.h>
void ddaline(int x1, int y1, int x2, int y2);
int main()
{
int gd=DETECT,gm,x1,y1,x2,y2;
 initgraph(&gd,&gm,"c:\\tc\\bgi");
int midx=getmaxx()/2, midy=getmaxy()/2;
 setcolor(WHITE);
  line(0,midy,getmaxx(),midy);
   line(midx,0,midx,getmaxy());
    printf(“Enter starting point: “);
     scanf(“%d%d”,&x1,&y1);
printf(“\nEnter ending point: “);
 scanf(“%d%d”,&x2,&y2);
  ddaline(x1,y1,x2,y2);
getch(); closegraph();
 return 0;
}
void ddaline(int x1, int y1, int x2, int y2)
{
int midx=getmaxx()/2, midy=getmaxy()/2;
 int dx=x2-x1, dy=y2-y1;
int pixel;
 if(abs(dx)>abs(dy))
pixel=dx;
else
pixel=dy;
dx=dx/pixel, dy=dy/pixel;
 int i=1, x=x1, y=y1;
  while(i<=pixel)
{
x=x+dx;
 y=y+dy;
putpixel(midx-x, midy+y, getcolor());
 i++
}
}

Output :
Enter Starting Point : 20 30
Enter Ending Point : 100 110