2009年12月18日 · In C99, the C header <math.h> defines nan(), nanf(), and nanl() that return different representations of NaN (as a double, float, and int respectively), and infinity (if …

2017年4月19日 · For freestanding C implementations (on which the <math.h> header may not be available) or when the NAN macro is not defined (which might happen even though NaN's …

2013年5月22日 · In C, NAN is declared in <math.h>. In C++, std::numeric_limits<double>::quiet_NaN() is declared in <limits> . But for checking whether a …

Relational operators may raise the "invalid" floating-point exception when argument values are NaNs. For a NaN and a numeric value, or for two NaNs, just the unordered relationship is true. …

2009年2月21日 · nan results from the operation 0.f/0.f, or 0.0/0.0. nan is a terrible nemesis to the stability of your code that must be detected and prevented very carefully 1. The properties of …

2017年11月1日 · I am very much a beginner to programming in C so please help out here. I am trying to write a program that loops asking the user to enter a number, if the number is positive …

2014年10月13日 · A bit-wise example of a IEEE floating-point standard single precision (32-bit) NaN: s111 1111 1axx xxxx xxxx xxxx xxxx xxxx where s is the sign, x is the payload, and a …

2014年10月6日 · A quiet NaN propagates through almost every arithmetic operation without raising a floating-point exception; a signaling NaN generally raises a floating-point exception …

2009年1月13日 · In addition to the previous correct answers it is probably worth pointing out that "Not a Number" (NaN) in its general usage is not equivalent to a string that cannot be …

It's hard to imagine an implementation that a) supports NaN values, but b) doesn't have them behave per IEEE 754. On any sane implementation, a < b is well-defined and has the value of …