Draw a Line : DDA Line Drawing Algorithm

C Program

#include <graphics.h>
#include <stdio.h>
#include <conio.h>
#include <math.h>
void main() {
	int gd = DETECT, gm = DETECT, s, dx, dy, m, x1, y1, x2, y2;
	float xi, yi, x, y;
	clrscr();
	printf("Enter the sarting point x1 & y1\n");
	scanf("%d%d", &x1, &y1);
	printf("Enter the end point x2 & y2\n");
	scanf("%d%d", &x2, &y2);
	initgraph(&gd, &gm, "");
	cleardevice();
	dx = x2 - x1;
	dy = y2 - y1;
	if (abs(dx) > abs(dy))
		s = abs(dx); else
		s = abs(dy);
	xi = dx / (float) s;
	yi = dy / (float) s;
	x = x1;
	y = y1;
	putpixel(x1, y1, 4);
	for (m = 0; m < s; m++) {
		x += xi;
		y += yi;
		putpixel(x, y, 4);
	}
	getch();
}