mirror of
https://github.com/nlohmann/json.git
synced 2026-10-12 10:13:13 +00:00
87 lines
2.2 KiB
Markdown
87 lines
2.2 KiB
Markdown
# <small>nlohmann::basic_json::</small>is_number_integer
|
|
|
|
```cpp
|
|
constexpr bool is_number_integer() const noexcept;
|
|
```
|
|
|
|
This function returns `#!cpp true` if and only if the JSON value is a signed or unsigned integer number. This excludes
|
|
floating-point values.
|
|
|
|
## Return value
|
|
|
|
`#!cpp true` if type is an integer or unsigned integer number, `#!cpp false` otherwise.
|
|
|
|
## Exception safety
|
|
|
|
No-throw guarantee: this member function never throws exceptions.
|
|
|
|
## Complexity
|
|
|
|
Constant.
|
|
|
|
## Examples
|
|
|
|
??? example
|
|
|
|
The following code exemplifies `is_number_integer()` for all JSON types.
|
|
|
|
```cpp
|
|
#include <iostream>
|
|
#include <nlohmann/json.hpp>
|
|
|
|
using json = nlohmann::json;
|
|
|
|
int main()
|
|
{
|
|
// create JSON values
|
|
json j_null;
|
|
json j_boolean = true;
|
|
json j_number_integer = 17;
|
|
json j_number_unsigned_integer = 12345678987654321u;
|
|
json j_number_float = 23.42;
|
|
json j_object = {{"one", 1}, {"two", 2}};
|
|
json j_array = {1, 2, 4, 8, 16};
|
|
json j_string = "Hello, world";
|
|
json j_binary = json::binary({1, 2, 3});
|
|
|
|
// call is_number_integer()
|
|
std::cout << std::boolalpha;
|
|
std::cout << j_null.is_number_integer() << '\n';
|
|
std::cout << j_boolean.is_number_integer() << '\n';
|
|
std::cout << j_number_integer.is_number_integer() << '\n';
|
|
std::cout << j_number_unsigned_integer.is_number_integer() << '\n';
|
|
std::cout << j_number_float.is_number_integer() << '\n';
|
|
std::cout << j_object.is_number_integer() << '\n';
|
|
std::cout << j_array.is_number_integer() << '\n';
|
|
std::cout << j_string.is_number_integer() << '\n';
|
|
std::cout << j_binary.is_number_integer() << '\n';
|
|
}
|
|
|
|
```
|
|
|
|
Output:
|
|
|
|
```json
|
|
false
|
|
false
|
|
true
|
|
true
|
|
false
|
|
false
|
|
false
|
|
false
|
|
false
|
|
|
|
```
|
|
|
|
## See also
|
|
|
|
- [is_number()](is_number.md) check if the value is a number
|
|
- [is_number_unsigned()](is_number_unsigned.md) check if the value is an unsigned integer number
|
|
- [is_number_float()](is_number_float.md) check if the value is a floating-point number
|
|
|
|
## Version history
|
|
|
|
- Added in version 1.0.0.
|
|
- Extended to also return `#!cpp true` for unsigned integers in 2.0.0.
|