Program for DDA Line Drawing Algorithm in C++

//This code is tested in Code Blocks

#include <iostream>
#include <graphics.h>
using namespace std;
void dda(float,float,float,float);
int main()
{
    float x1,y1,x2,y2;
    cout<<"Enter the value of x1 and y1 : ";
    cin>>x1>>y1;
    cout<<"Enter the value of x2 and y2: ";
    cin>>x2>>y2;
    dda(x1,y1,x2,y2);
}
void dda(float x1,float y1,float x2,float y2)
{
    float x,y,dx,dy,step;
    int i,gd=DETECT,gm;
    char path[] = "";
    initgraph(&gd,&gm,path);
    dx=x2-x1;
    dy=y2-y1;

    if(dx>=dy)
    {
        step=abs(dx);
    }
    else
    {
       step=abs(dy);
    }
    dx=dx/step;
    dy=dy/step;
    x=x1;
    y=y1;
    i=1;
    while(i<=step)
    {
        putpixel(x,y,WHITE);
        x=x+dx;
        y=y+dy;
        i=i+1;
    }
    getch();
    closegraph();
}

OUTPUT: