How can I pass a member function where a free function is expected?

Question

The question is the following: consider this piece of code:

#include 


class aClass
{
public:
    void aTest(int a, int b)
    {
        prin         


        

Answer 1

If you actually don't need to use the instance a (i.e. you can make it static like @mathengineer 's answer) you can simply pass in a non-capture lambda. (which decay to function pointer)

---

#include 

class aClass
{
public:
   void aTest(int a, int b)
   {
      printf("%d + %d = %d", a, b, a + b);
   }
};

void function1(void (*function)(int, int))
{
    function(1, 1);
}

int main()
{
   //note: you don't need the `+`
   function1(+[](int a,int b){return aClass{}.aTest(a,b);}); 
}

Wandbox

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note: if aClass is costly to construct or has side effect, this may not be a good way.