[zooweemama]

Pretty sure that the compiler optimizes this and there is no performance loss.

[meindnoch]

You're wrong.

  if (cheapCheck() && expensiveCheck()) { ... }

is not equivalent to

  bool cheap = cheapCheck();
  bool expensive = expensiveCheck();
  if (cheap && expensive) { ... }

unless we're in a lazy pure functional language.

[IshKebab]

That depends. In some cases the compiler will be able to determine that `expensiveCheck()` has no side effects and make them equivalent. But you can't really rely on it.

And in any case the author misidentified the problem and solution. The problem is that C++ coerces bool to int. I'm 99% sure there's a warning for that that you can turn into an error.

[grok22]

In theory, if this is the case (or the case in other comments about null pointer use and such), you would/could write it as:

   bool cheap = cheapCheck();
   bool expensive = cheap && expensiveCheck();
   if (expensive) { ... }

[lazypenguin]

Can you prove this?