stdnumericlimits

stdnumericlimits is a C++ template class defined in the <limits> header. It provides a way to query the properties of arithmetic types. For any given fundamental arithmetic type such as int, float, or double, std::numeric_limits<T> offers compile-time constants and functions that describe the type's characteristics.

These characteristics include the minimum and maximum representable values, the number of bits used to represent the value, and information about rounding and precision. For instance, std::numeric_limits<int>::min() returns the smallest possible value for an int, while std::numeric_limits<float>::max() gives the largest representable finite value for a float. Other useful members include is_integer, is_signed, digits, and epsilon.

The primary purpose of std::numeric_limits is to provide portable and reliable access to these type-specific properties, allowing developers to write code that behaves correctly across different platforms and compilers without hardcoding magic numbers. It's particularly important when dealing with operations that might overflow or underflow, or when precise control over numerical behavior is required. For example, you can check if a type is a floating-point type using std::numeric_limits<T>::is_iec559. This template is a fundamental tool for robust numerical programming in C++.