Thread: Overload False Operator

Code:

// Overload true.   
  public static bool operator true(ThreeD op) { 
    if((op.x != 0) || (op.y != 0) || (op.z != 0)) 
      return true; // at least one coordinate is non-zero 
    else 
      return false; 
  }   
 
  // Overload false. 
  public static bool operator false(ThreeD op) { 
    if((op.x == 0) && (op.y == 0) && (op.z == 0)) 
      return true; // all coordinates are zero 
    else 
      return false; 
  }   

public class TrueFalseDemo {   
  public static void Main() {   
    ThreeD a = new ThreeD(5, 6, 7);   
    ThreeD b = new ThreeD(10, 10, 10);   
    ThreeD c = new ThreeD(0, 0, 0);   
   
    Console.Write("Here is a: ");   
    a.show();   
    Console.Write("Here is b: ");   
    b.show();   
    Console.Write("Here is c: ");   
    c.show();   
    Console.WriteLine();   
   
    if(a) Console.WriteLine("a is true."); 
    else Console.WriteLine("a is false."); 
 
    if(b) Console.WriteLine("b is true."); 
    else Console.WriteLine("b is false."); 
 
    if(c) Console.WriteLine("c is true."); 
    else Console.WriteLine("c is false.");

So as you knows, in any C based language, when you overload the true and false operators, you have to overload both of them. But the question is what invokes the false overload operator method? When the program reaches the if(a) Console.WriteLine("a is true."); This will invokes the true overload operator method and within the operator method, we already have the result of true and false. If the expression within the true overload operator method is true, then returns true, and if it is false, returns false.

Because within the if statement in main, the a, which is the object, is always assumed to be true. There is no way to invoke the false overload operator method. Just why we need it and what codes to write within the method?