Bresenham's Line (for slope 0 to 1)

/* Bresenham's Line Implementation for 0<=m<=1 and drawing from left to right. - Subhranath Chunder */

#include<stdio.h>
#include<conio.h>
#include<graphics.h>

void lineBres(int,int,int,int);
void setPixel(int,int);

void main()
{
 int x1,y1,x2,y2;
 int driver=DETECT,mode;

 clrscr();
 printf("Enter the co-ordinates of the first point (a b): ");
 scanf("%d %d",&x1,&y1);
 printf("Enter the co-ordinates of the second point (a b): ");
 scanf("%d %d",&x2,&y2);
 printf("<Press any key to continue>");
 getch();

 initgraph(&driver,&mode,"F:\\TC\\BGI");
 lineBres(x1,y1,x2,y2);
 getch();
 closegraph();
}

void lineBres(int x1,int y1,int x2,int y2)
{
 float error,m;
 int x,y;
 m=(float)(y2-y1)/(x2-x1);
 error=0;
 y=y1;
 x=x1;
 setPixel(x,y);
 while(x<=x2)
 {
    error+=m;
    if(error>.5)
    {
       y+=1;
       --error;
    }
    ++x;
    setPixel(x,y);
 }
}

void setPixel(int x,int y)
{
 putpixel(x,y,2);
}