1# basic_json::is_number 2 3```cpp 4constexpr bool is_number() const noexcept; 5``` 6 7This function returns `#!cpp true` if and only if the JSON value is a number. This includes both integer (signed and 8unsigned) and floating-point values. 9 10## Return value 11 12`#!cpp true` if type is number (regardless whether integer, unsigned integer or floating-type), `#!cpp false` otherwise. 13 14## Exception safety 15 16No-throw guarantee: this member function never throws exceptions. 17 18## Complexity 19 20Constant. 21 22## Possible implementation 23 24```cpp 25constexpr bool is_number() const noexcept 26{ 27 return is_number_integer() || is_number_float(); 28} 29``` 30 31## Example 32 33??? example 34 35 The following code exemplifies `is_number()` for all JSON types. 36 37 ```cpp 38 --8<-- "examples/is_number.cpp" 39 ``` 40 41 Output: 42 43 ```json 44 --8<-- "examples/is_number.output" 45 ``` 46 47## Version history 48 49- Added in version 1.0.0. 50- Extended to also return `#!cpp true` for unsigned integers in 2.0.0. 51