Preprocessor if in c++

Question

I had the following structure:

#if COND
  ...
#endif
#elif COND2
  ...
#else
  ...
#endif

I have to replace elif with two statements: else and if:

#if COND
  ...
#endif
#else
  #if COND2
     ...
  #endif
#else     // error: #else after #else
  ...
#endif

What's wrong?

p.s. No I see what's wrong but how to write it without errors?

Why do you have to replace it in the first place? What’s the problem with the first version (well, except for the wrong #endif)? — Konrad Rudolph
– Konrad Rudolph, Commented Mar 9, 2012 at 11:22
@KonradRudolph stackoverflow.com/questions/9631762/missing-binary-operator-c — Max Frai
– Max Frai, Commented Mar 9, 2012 at 11:23

Luchian Grigore · Accepted Answer · 2012-03-09 11:17:11Z

2

You can't have two #else statements in the same #if.

The correct version would be:

#if COND
  ...
#else
  #if COND2
     ...
  #else
     ...
  #endif
#endif

answered Mar 9, 2012 at 11:17

Luchian Grigore

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2 Comments

Okay, I see that. But how to replace in my case?

@Ockonal actually, this version is the correct one. You also had an #endif before the first #else.