Standard C++ Library User Guide and Tutorial

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Numeric Limit Members

Since a number of the fields in the numeric_limits structure are meaningful only for floating

point values, it is useful to separate the description of the members into common fields and

floating-point specific fields.

Members Common to All Types

The following table summarizes the information available through the numeric_limits static

member data fields and functions.

Type Name Meaning

bool is_specialized true if a specialization exists, false otherwise

T min() smallest finite value

T max() largest finite value

int radix the base of the representation

int digits number of radix digits that can be represented without change

int digits10 number of base-10 digits that can be represented without change

bool is_signed true if the type is signed

bool is_integer true if the type is integer

bool is_exact true if the representation is exact

bool is_bounded true if representation is finite

bool is_modulo true if type is modulo

bool traps true if trapping is implemented for the type

Radix represents the internal base for the representation. For example, most machines use a

base 2 radix for integer data values, however some may also support a representation, such as

BCD, that uses a different base. The digits field then represents the number of such radix values

that can be held in a value. For an integer type, this would be the number of non-sign bits in the