Thread: M_PI

  1. 03-16-2009 #1
    MarkZWEERS
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    M_PI

    Hi everyone,

    Does anyone know if they have dropped the constant "M_PI" in the <cmath> or <math.h> header? Until now, I've always used it.. :-(

    Thanks for your answer!

    Mark
  2. 03-16-2009 #2
    laserlight
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    I do not think that it was ever part of standard C++ (or standard C).
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way
  3. 03-16-2009 #3
    brewbuck
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    It's not standard, although most implementations provide it. I'd just define it myself:

    Code:
    #include <cmath>

#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif
    Code:
    //try
//{
	if (a) do { f( b); } while(1);
	else   do { f(!b); } while(1);
//}
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