'NULL' : undeclared identifier

When working with pointers when I use separate files (and sometimes when I use 1 file) I get:

error C2065: 'NULL' : undeclared identifier

I did some searching but none of these worked:

Code:

---

#define NULL

---

Code:

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#define NULL 0

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Code:

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#define NULL ((void *) 0)

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Code:

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#ifndef NULL
#ifdef __cplusplus
#define NULL    0
#else
#define NULL    ((void *)0)
#endif
#endif

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Code:

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#include <cstdlib>

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In fact, compiling using any these usually crashes the program.

Well actually, IIRC, you don't even need NULL for anything in C++, since it just evaluates to zero. And defining NULL as zero isn't what makes your program crash. It's your program doing something it shouldn't elsewhere. Like running off the end of an array, dereferencing null pointers, etc etc.

Quzah.