# nlohmann::basic_json::operator!=
```cpp
// until C++20
bool operator!=(const_reference lhs, const_reference rhs) noexcept; // (1)
template
bool operator!=(const_reference lhs, const ScalarType rhs) noexcept; // (2)
template
bool operator!=(ScalarType lhs, const const_reference rhs) noexcept; // (2)
// since C++20
class basic_json {
bool operator!=(const_reference rhs) const noexcept; // (1)
template
bool operator!=(ScalarType rhs) const noexcept; // (2)
};
```
1. Compares two JSON values for inequality according to the following rules:
- The comparison always yields `#!cpp false` if (1) either operand is discarded, or (2) either operand is `NaN` and
the other operand is either `NaN` or any other number.
- Otherwise, returns the result of `#!cpp !(lhs == rhs)` (until C++20) or `#!cpp !(*this == rhs)` (since C++20).
2. Compares a JSON value and a scalar or a scalar and a JSON value for inequality by converting the scalar to a JSON
value and comparing both JSON values according to 1.
## Template parameters
`ScalarType`
: a scalar type according to `std::is_scalar::value`
## Parameters
`lhs` (in)
: first value to consider
`rhs` (in)
: second value to consider
## Return value
whether the values `lhs`/`*this` and `rhs` are not equal
## Exception safety
No-throw guarantee: this function never throws exceptions.
## Complexity
Linear.
## Notes
!!! note "Comparing `NaN`"
`NaN` values are unordered within the domain of numbers.
The following comparisons all yield `#!cpp false`:
1. Comparing a `NaN` with itself.
2. Comparing a `NaN` with another `NaN`.
3. Comparing a `NaN` and any other number.
## Examples
??? example
The example demonstrates comparing several JSON types.
```cpp
--8<-- "examples/operator__notequal.cpp"
```
Output:
```json
--8<-- "examples/operator__notequal.output"
```
??? example
The example demonstrates comparing several JSON types against the null pointer (JSON `#!json null`).
```cpp
--8<-- "examples/operator__notequal__nullptr_t.cpp"
```
Output:
```json
--8<-- "examples/operator__notequal__nullptr_t.output"
```
## Version history
1. Added in version 1.0.0. Added C++20 member functions in version 3.11.0.
2. Added in version 1.0.0. Added C++20 member functions in version 3.11.0.