Lambda Functions

Lambda functions provide their functionality in-place. The compiler gets its information right on the spot and has therefore excellent optimisation potential. Lambda functions can receive their arguments by value or by reference. They can capture the variables of their defining environment by value or by reference as well.

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 generally faster than a function, or a function object and easier to understand.