I cannot pass lambda as std::function

Question

Let\'s focus on this example:

template
class C{
    public:
    void func(std::vector& vec, std::function

        

Answer 1

It's because the argument (std::function) is a reference. It should be:

void func(std::vector& vec, std::function f)
                                                                ^  ^
                                                                   |
                                                                   f not a reference

So that the argument can be converted to the parameter type.

Also, the type of the function should match. I.e. it should accept a string reference.