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Editorial Team
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Asked: 2026-05-22T03:23:35+00:00

Suppose I have the following in C++: char buffer[SIZE]; char * ptr = &buffer[SIZE];

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Suppose I have the following in C++:

char buffer[SIZE];
char * ptr = &buffer[SIZE];

where ptr‘s value is never dereferenced. Is this even legal to do C++? That is use the memory address one stride from the last element of an array (say as a special value to compare to)?

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1 Answer

  1. Editorial Team

    If you said:

    char buffer[SIZE];
char * ptr = & buffer[SIZE];

    then yes, it is legal. You are specifically allowed by the C++ standard to use the one-past-the-end of an array in this manner, and it is used extensively when (for example) working with iterators.

    Edit: But see comments by litb and Steve Jessop. If you want to be entirely politcally correct, you probably want:

    char * ptr = buffer + SIZE;

    Either way, the one-past-the-end address is a valid address – the perhaps not quite clear issue (as I understand it) is whether you are allowed to dereference it.

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