How do you do casting with pointers?

Answer 1

The question posed is a bit difficult to answer as there are no context specific clues (are we talking C/C++ here, or something more general such as object references in Java?), so an answer relating to C is given. Many times when writing a program it becomes necessary to pass a reference to a piece of data to a function, or perhaps to store a reference to a piece of data -- especially when writing a data structure that stores references to many different data (of many different types). In such a case the easiest way is to create a void pointer reference (void*). Now "casting the pointer" in order to correctely dereference the data is simply a matter of knowing the data type you are casting to, and indicating that it is a reference to a piece of data of that type. For example, suppose you have a structure called foo, that contains a field called bar, then: void printbar(void* myfoo) { printf("Bar = %s\n", (struct foo*)myfoo->bar); } should solve your problem. In this example you are indicating that the void pointer myfoo (which holds a memory reference) should be cast to a pointer that holds a memory reference to a piece of data of the type stuct foo.