以下C代码有什么问题

Question

I am using VC2010. I defined FALSE to be false using

#define FALSE=false

and then I tried to use it as follows

bool *bPtr;
if(some condition)
*bPtr=FALSE;

the compiler flags FALSE and says "Expected an expression".

I used false instead of the defined 'FALSE' and it accepts it. I am wondering as what could be the problem.

You might tell me not to define and so not to use FALSE. well, I am not using it.

I just want to know the problem.

Answer 1

Just this:

#define FALSE false

with whitespace and without = .

Answer 2

You shouldn't put = in the definition statement:

#define FALSE false

The problem is that the preprocessor will replace every FALSE with =false , so you will have:

*bPtr==false;

And this is not legal as you see.

Answer 3

try defining like this:

#ifndef (FALSE)
#define FALSE (0)
#endif