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title: "constexpr Lambda Expressions in C++ | Microsoft Docs"
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# constexpr Lambda Expressions in C++
**Visual Studio 2017 version 15.3 and later** (available with [/std:c++17](../build/reference/std-specify-language-standard-version.md)): A lambda expression may be declared as `constexpr` or used in a contant expression when the initialization of each data member that it captures or introduces is allowed within a constant expression.  

```cpp
    int y = 32;
	auto answer = [y]() constexpr 
	{
		int x = 10;
		return y + x; 
	};

    constexpr int Increment(int n) 
    {
	    return [n] { return n + 1; }();
    }

``` 
A lambda is implicitly `constexpr` if its result satisfies the requirements of a `constexpr` function:
```cpp
	auto answer = [](int n) 
	{
		return 32 + n; 
	};

	constexpr int response = answer(10);
``` 
If a lambda is implicitly or explicitly `constexpr`, and you convert it to a function pointer, the resulting function is also `constexpr`:

```cpp
	auto Increment = [](int n)
	{
		return n + 1;
	};

	constexpr int(*inc)(int) = Increment;
```
  
## See Also  
 [C++ Language Reference](../cpp/cpp-language-reference.md)   
 [Function Objects in the C++ Standard Library](../standard-library/function-objects-in-the-stl.md)   
 [Function Call](../cpp/function-call-cpp.md)   
 [for_each](../standard-library/algorithm-functions.md#for_each)