Example of Forward References
class Link { // now provide the full link implementationpublic: // data fields are public int value; Link * forwardLink; Link * backwardLink; // constructor defined in-line Link (int v, Link * f, Link * b) { value = v; forwardLink = f; backwardLink = b; } // prototype, definition given elsewhere // requires knowledge of class List void addBefore (int val, List * theList);