Use an explicit conversion

   
  
/*
C#: The Complete Reference 
by Herbert Schildt 

Publisher: Osborne/McGraw-Hill (March 8, 2002)
ISBN: 0072134852
*/


// Use an explicit conversion. 
 
using System; 
 
// A three-dimensional coordinate class. 
class ThreeD { 
  int x, y, z; // 3-D coordinates   
 
  public ThreeD() { x = y = z = 0; } 
  public ThreeD(int i, int j, int k) { x = i; y = j; z = k; } 
 
  // Overload binary +. 
  public static ThreeD operator +(ThreeD op1, ThreeD op2) 
  { 
    ThreeD result = new ThreeD(); 
 
    result.x = op1.x + op2.x;  
    result.y = op1.y + op2.y;  
    result.z = op1.z + op2.z;  
 
    return result; 
  } 
 
  // This is now explicit. 
  public static explicit operator int(ThreeD op1) 
  { 
    return op1.x * op1.y * op1.z; 
  } 
   
  // Show X, Y, Z coordinates. 
  public void show() 
  { 
    Console.WriteLine(x + ", " + y + ", " + z); 
  } 
} 
 
public class ThreeDDemo7 { 
  public static void Main() { 
    ThreeD a = new ThreeD(1, 2, 3); 
    ThreeD b = new ThreeD(10, 10, 10); 
    ThreeD c = new ThreeD(); 
    int i; 
 
    Console.Write("Here is a: "); 
    a.show(); 
    Console.WriteLine(); 
    Console.Write("Here is b: "); 
    b.show(); 
    Console.WriteLine(); 
 
    c = a + b; // add a and b together 
    Console.Write("Result of a + b: "); 
    c.show(); 
    Console.WriteLine(); 
 
    i = (int) a; // explicitly convert to int -- cast required 
    Console.WriteLine("Result of i = a: " + i); 
    Console.WriteLine(); 
 
    i = (int)a * 2 - (int)b; // casts required 
    Console.WriteLine("result of a * 2 - b: " + i); 
 
  } 
}