Benefits of using short-circuit evaluation

Question

boolean a = false, b = true;
if ( a && b ) { ... };

In most languages, b will not get evaluated because a is fals

Answer 1

I honestly wouldn't worry about it. Testing a boolean is really fast. Short-circuiting only gets interesting / useful when the second expression has side effects:

if ( ConfirmAction() && DestroyAllData() )
   Reboot();

...or depends on the first test:

if ( myDodgyVar != null && myDodgyVar.IsActive() )
   DoSomethingWith(myDodgyVar);