Math Constants

 

For the latest documentation on Visual Studio 2017 RC, see Visual Studio 2017 RC Documentation.

#define _USE_MATH_DEFINES // for C++  
#include <cmath>  
  
#define _USE_MATH_DEFINES // for C  
#include <math.h>  

The following symbols are defined for the values of their indicated expressions:

SymbolExpressionValue
M_Ee2.71828182845904523536
M_LOG2Elog2(e)1.44269504088896340736
M_LOG10Elog10(e)0.434294481903251827651
M_LN2ln(2)0.693147180559945309417
M_LN10ln(10)2.30258509299404568402
M_PIpi3.14159265358979323846
M_PI_2pi/21.57079632679489661923
M_PI_4pi/40.785398163397448309616
M_1_PI1/pi0.318309886183790671538
M_2_PI2/pi0.636619772367581343076
M_2_SQRTPI2/sqrt(pi)1.12837916709551257390
M_SQRT2sqrt(2)1.41421356237309504880
M_SQRT1_21/sqrt(2)0.707106781186547524401

Math Constants are not defined in Standard C/C++. To use them, you must first define _USE_MATH_DEFINES and then include cmath or math.h.

The file ATLComTime.h includes math.h when your project is built in Release mode. If you use one or more of the math constants in a project that also includes ATLComTime.h, you must define _USE_MATH_DEFINES before you include ATLComTime.h.

Global Constants

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