Lambda Functions

Lambda functions provide in-place functionality. The compiler gets a lot of insight and has therefore great optimisation potential. Lambda functions can receive their arguments by value or by reference. They can capture their environment by value, by reference and with C++14 by move.

std::vector<int> myVec{1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
std::for_each(myVec.begin(), myVec.end(), [](int& i){ i= i*i; });
                                        // 1 4 9 16 25 36 49 64 81 100

Lambda functions should be your first choice

If the functionality of your callable is short and self-explanatory, use a lambda function. A lambda function is, in general, faster and easier to understand.