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74 lines
1.6 KiB
Markdown
74 lines
1.6 KiB
Markdown
# <small>nlohmann::basic_json::</small>operator=
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```cpp
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basic_json& operator=(basic_json other) noexcept (
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std::is_nothrow_move_constructible<value_t>::value &&
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std::is_nothrow_move_assignable<value_t>::value &&
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std::is_nothrow_move_constructible<json_value>::value &&
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std::is_nothrow_move_assignable<json_value>::value &&
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std::is_nothrow_move_assignable<json_base_class_t>::value
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);
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```
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Copy assignment operator. Copies a JSON value via the "copy and swap" strategy: It is expressed in terms of the copy
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constructor, destructor, and the `swap()` member function.
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## Parameters
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`other` (in)
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: value to copy from
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## Exception safety
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Strong guarantee: if an exception is thrown while copying `other`, there are no changes to `#!cpp *this`.
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## Complexity
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Linear.
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## Examples
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??? example
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The code below shows and example for the copy assignment. It creates a copy of value `a` which is then swapped with
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`b`. Finally, the copy of `a` (which is the null value after the swap) is destroyed.
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```cpp
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#include <iostream>
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#include <nlohmann/json.hpp>
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using json = nlohmann::json;
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int main()
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{
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// create JSON values
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json a = 23;
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json b = 42;
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// copy-assign a to b
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b = a;
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// serialize the JSON arrays
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std::cout << a << '\n';
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std::cout << b << '\n';
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}
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```
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Output:
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```json
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23
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23
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```
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## See also
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- [basic_json](basic_json.md) create a JSON value
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- [swap](swap.md) exchanges the contents of two JSON values
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## Version history
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- Added in version 1.0.0.
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