find quadrant of a point on graph without if condition

Question

4.00/5 (1 vote)

See more:

How can i find the position (quadrant or axis) of a point on a graph without using any conditon (if, while, for...etc). The user will provide coordinates(x,y) of the point.
Language=C or CPP

Posted 10-Dec-09 0:34am

GPUToaster™

Add a Solution

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

CPallini · Accepted Answer · 2009-12-10T02:42:00

// requires <math.h>

int quadrant(double x, double y)
{
  static int q[]={3, 4, 2, 1};
  int sx = ((int)(x/fabs(x)) + 1)/2;
  int sy = ((int)(y/fabs(y)) + 1); 
  return q[sx+sy];
}

you may use, as well, atan2 instead of fabs:

int quadrant(double x, double y)
{
  static int q[]={3, 4, 2, 1};
  int i = (int)((atan2(y,x)/atan2(1.,0.))+2.0); 
  return q[i];
}

Please note, the function gives wrong result for x=0.0 or/and y=0.0 input values (such points are on the boundary of the quadrants).
:)