Message-Id: <3.0.5.32.19981002154028.0098f7f0@dictator.nt.tuwien.ac.at>
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Date: Fri, 02 Oct 1998 15:40:28 +0200
To: djgpp AT delorie DOT com
From: Anton Helm <tony AT dictator DOT nt DOT tuwien DOT ac DOT at>
Subject: Re: Tank Movement
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Dear cbroo AT iafrica DOT com (Chris Brooker),

Would you mind giving a valid email address if you expect answers ?

Tony




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At 07:14 02.10.98 GMT, you wrote:

>Here are the functions:
>
>double dir_degrees(int x1, int y1, int y2, int x2)
>{
>	int v1, v2;
>	double dir;
>	v1 = y1 - y2;
>	v2 = x1 - x2;
>	if (v2 == 0) 
>	 v2++; //Stops division by zero errors
>	dir = 57 * atan(v1 / v2);
>	return dir;
>}

Consider using atan2:


#include <math.h>

double dir_degrees(int x1, int y1, int y2, int x2)
  {
  return  atan2(y1-y2, x1-x2) * 180.0 / PI;
  }




Tony



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