C++ Primer, Fifth Edition

Using Function Pointers

When we use the name of a function as a value, the function is automatically converted to a pointer. For example, we can assign the address of lengthCompare to pf as follows:

pf = lengthCompare;  // pf now points to the function named lengthComparepf = &lengthCompare; // equivalent assignment: address-of operator is optional

Moreover, we can use a pointer to a function to call the function to which the pointer points. We can do so directly—there is no need to dereference the pointer:

bool b1 = pf("hello", "goodbye");    // calls lengthComparebool b2 = (*pf)("hello", "goodbye"); // equivalent callbool b3 = lengthCompare("hello", "goodbye"); // equivalent call

There is no conversion between pointers to one function type ...