House by DDA Line Drawing Algorithm

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

void dda(float x1, float y1, float x2, float y2){
    detectgraph(&gd,&gm);
    initgraph(&gd,&gm,"C:\\TC\\BGI");

    float x, y, dx, dy, length;
    int i, intx, inty;
    abs(x2 - x1) > abs(y2 - y1) ? (length = abs(x2 - x1)) : (length = abs(y2 - y1));
    dx = (x2 - x1) / length;
    dy = (y2 - y1) / length;
    dx >= 0 ? (x = x1 + 0.5) : (x = x1 - 0.5);
    dy >= 0 ? (y = y1 + 0.5) : (y = y1 - 0.5);
    for(i = 0, intx = x, inty = y; i <= length; i++, x += dx, y += dy, intx = x, inty = y)
        putpixel(intx, inty, 30);

    delay(100);
}
int main(){
    dda(50,100,100,100);
    dda(50,100,50, 50);
    dda(100, 100, 100, 50);
    dda(50, 50, 75, 0);
    dda(100, 50, 75, 0);
    dda(100, 50, 50, 50);
    closegraph();
    return 0;
}