To expand on Neil’s remark, std::numeric_limit<T> is available for any number type including floating point numbers, and if you dig through the comp.lang.c++ thread, you’ll see the mention that it might not be possible to define the static variables for floating point values. So, for consistency they decided to put both integral and floating points … Read more
It’s not actually zero, but it might look like zero if you inspect it using printf or NSLog by using %f. According to float.h (at least in Mac OS X 10.6.2), FLT_MIN is described as: /* Minimum normalized positive floating-point number, b**(emin – 1). */ Note the positive in that sentence: FLT_MIN refers to the … Read more
The -1 is because integers start at 0, but our counting starts at 1. So, 2^32-1 is the maximum value for a 32-bit unsigned integer (32 binary digits). 2^32 is the number of possible values. To simplify why, look at decimal. 10^2-1 is the maximum value of a 2-digit decimal number (99). Because our intuitive … Read more
By definition, for floating types, min returns the smallest positive value the type can encode, not the lowest. If you want the lowest value, use numeric_limits::lowest instead. Documentation: http://en.cppreference.com/w/cpp/types/numeric_limits/min As for why it is this way, I can only speculate that the Standard committee needed to have a way to represent all forms of extreme … Read more
You need to include the header file <limits>, which is where std::numeric_limits is defined. Your Mac compiler was helping you out by automatically including that header file; however, you should not rely on that behavior and explicitly include any header files you need.
Update Provided a simple test case that shows that Boost Spirit is capable to handle all varieties of special values in this area. See below: Boost Spirit (FTW). The standard The only normative information in this area that I’ve been able to find is in sections 7.19.6.1/7.19.6.2 of the C99 standard. Sadly, the corresponding sections … Read more
At least if std::numeric_limits::is_iec559 (IEEE 754) is true (which guarantees, that std::numeric_limits::has_infinity is also true), you can express positive and negative infinity values the way you already stated. Short explanation of IEEE 754-1985 infinity values from Wikipedia: ……snip…… The biased-exponent field is filled with all 1 bits to indicate either infinity or an invalid result … Read more
Your problem is caused by the <Windows.h> header file that includes macro definitions named max and min: #define max(a,b) (((a) > (b)) ? (a) : (b)) Seeing this definition, the preprocessor replaces the max identifier in the expression: std::numeric_limits<size_t>::max() by the macro definition, eventually leading to invalid syntax: std::numeric_limits<size_t>::(((a) > (b)) ? (a) : (b)) … Read more
This commonly occurs when including a Windows header that defines a min or max macro. If you’re using Windows headers, put #define NOMINMAX in your code, or build with the equivalent compiler switch (i.e. use /DNOMINMAX for Visual Studio). Note that building with NOMINMAX disables use of the macro in your entire program. If you … Read more
In C++: #include <limits> then use int imin = std::numeric_limits<int>::min(); // minimum value int imax = std::numeric_limits<int>::max(); std::numeric_limits is a template type which can be instantiated with other types: float fmin = std::numeric_limits<float>::min(); // minimum positive value float fmax = std::numeric_limits<float>::max(); In C: #include <limits.h> then use int imin = INT_MIN; // minimum value int … Read more