Chapter 8 Quick Reference To Do this Copy a value type variable Simply make the copy. Because the variable is a value type, you will have two copies of the same value. For example: int i = 42; int copyi = i; Copy a reference type variable Simply make the copy. Because the variable is a reference type, you will have two references to the same object. For example: Circle c = new Circle(42); Circle refc = c; Pass an argument to a ref parameter Prefix the argument with the ref keyword. This makes the parameter an alias for the actual argument rather than a copy of the argument. For example: static void Main() { int arg = 42; DoWork(ref arg); Console.WriteLine(arg); } Pass an argument to an out parameter Prefix the argument with the out keyword. This makes the parameter an alias for the actual argument rather than a copy of the argument. For example: static void Main() { int arg = 42; DoWork(out arg); Console.WriteLine(arg); } Box a value Initialize or assign a variable of type object to the value. For example: object o = 42; Unbox a value Cast the object reference that refers to the boxed value to the type of the value. For example: int i = (int)o; . Chapter 8 Quick Reference To Do this Copy a value type variable Simply make the copy int copyi = i; Copy a reference type variable Simply make the copy. Because the variable is a reference type, you will have two references to the same