Let me show a nice C/C++ trick I just found out:

Instead of writing:

if (function1())
  function2();

you could write:

function1() && function2();

because the right side of the && operator is only evaluated (in this case: called), when function1() is true (returns a non-null value).

Subsequently, instead of:

if (!function1()) // or if (function1()==0) etc.
  function2();

you could write:

function1() || function2();

Cool, eh?