What are some examples of capturing variables in C++ lambda expressions?

What are some examples of capturing variables in C++ lambda expressions?

In C++, lambda expressions can capture variables from their surrounding scope. For example:

int x = 10;
auto lambda = [&x]() { return x + 5; };
std::cout << lambda(); // Outputs 15

This captures x by reference.

Can you show me an example of capturing by value?

Sure! Here's an example of capturing by value:

int y = 20;
auto lambdaByValue = [y]() { return y + 10; };
std::cout << lambdaByValue(); // Outputs 30

In this case, y is captured by value.

What happens if the captured variable changes after the lambda is created?

If you capture by reference, the lambda will reflect changes to the variable. For example:

int z = 30;
auto lambdaRef = [&z]() { return z; };
z = 40;
std::cout << lambdaRef(); // Outputs 40

But if you capture by value, it won't reflect changes.

Are there any limitations to using lambda expressions?

Yes, lambda expressions cannot capture variables that are not in scope, and they cannot be used to capture non-copyable types by value.