|
Safe Numerics |
A type is Numeric if it has the properties of a number.
More specifically, a type T is Numeric if there exists
specialization of std::numeric_limits<T>. See the
documentation for standard library class numeric_limits. The standard
library includes such specializations for all the primitive numeric types.
Note that this concept is distinct from the C++ standard library type
traits is_integral and is_arithmetic. These
latter fulfill the requirement of the concept Numeric. But there are types
T which fulfill this concept for which is_arithmetic<T>::value
== false. For example see
safe_signed_integer<int>.
T, U, V |
A type that is a model of the Numeric |
t, u |
An object of type modeling Numeric |
os |
An object of type std::base_ostreami |
is |
An object of type std::base_istream |
std::numeric_limits<T> |
The numeric_limits class template provides a C++ program with information about various properties of the implementation's representation of the arithmetic types. See C++ standard 18.3.2.2. |
In addition to the expressions defined in Assignable the following expressions must be valid. Any operations which result in integers which cannot be represented as some Numeric type will throw an exception.
Table 1. General
| Expression | Return Value | |
|---|---|---|
std::numeric_limits<T>.is_bounded
|
true | |
std::numeric_limits<T>.is_specialized
|
true | |
|
os &i | |
|
is & |
Table 2. Unary Operators
| Expression | Return Type | Semantics |
|---|---|---|
-t |
T | Invert sign |
+t |
T | unary plus - a no op |
t-- |
T | post decrement |
t++ |
T | post increment |
--t |
T | pre decrement |
++t |
T | pre increment |
~ |
T | complement |
Table 3. Binary Operators
| Expression | Return Type | Semantics |
|---|---|---|
t - u |
V | subtract u from t |
t + u |
V | add u to t |
t * u |
V | multiply t by u |
t / u |
T | divide t by u |
t % u |
T | t modulus u |
t << u |
T | shift t left u bits |
t >> u |
T | shift t right by u bits |
t < u |
bool | true if t less than u, false otherwise |
t <= u |
bool | true if t less than or equal to u, false otherwise |
t > u |
bool | true if t greater than u, false otherwise |
t >= u |
bool | true if t greater than or equal to u, false otherwise |
t == u |
bool | true if t equal to u, false otherwise |
t != u |
bool | true if t not equal to u, false otherwise |
t & u |
V | and of t and u padded out max # bits in t, u |
t | u |
V | or of t and u padded out max # bits in t, u |
t ^ u |
V | exclusive or of t and u padded out max # bits in t, u |
t = u |
T |
assign value of u to t |
t += u |
T |
add u to t and assign to t |
t -= u |
T |
subtract u from t and assign to t |
t *= u |
T |
multiply t by u and assign to t |
t /= u |
T |
divide t by u and assign to t |
t &= u |
T |
and t with u and assign to t |
t <<= u |
T | left shift the value of t by u bits |
t >>= u |
T | right shift the value of t by u bits |
t &= u |
T | and the value of t with u and assign to t |
t |= u |
T | or the value of t with u and assign to t |
t ^= u |
T | exclusive or the value of t with u and assign to t |