What does
int(*compare)(void* argu1, void*argu2);
mean? I have never seen something like this, it is in my binary search tree chapter and is it in the BST strucutre:
typdef struct{
int counter;
int(*compare)(void* argu1, void*argu2);
NODE* root;
}BST;
This is a variable named compare which is a pointer to a function. The function returns an int and receives two void * parameters.
Function pointers are frequently used for providing a way to generically compare two values of a type that some other function (such as a sorting or ordering routine) does not understand; the caller provides a function to do the comparison on the generic function's behalf.
It means compare is a pointer to a function having its both parameter of type void * and having return type int.
int(*compare)(void* argu1, void*argu2);
This is a variable declaration. The variable is a function pointer and its name is "compare". It can point to any function that returns an int and takes two void pointers.
The code declares a variable named "compare". This variable is a function pointer type, meaning you can assign a function name to this variable, and later invoke this function just like making a regular function call. For further reading, you may refer to early binding vs. late binding.
