Calculating # of Elements in Array

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  1. #1
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    Question Calculating # of Elements in Array

    There is something I don't really understand about calculating number of elements in Array.


    int array[] = { 10, 20, 30, 40 };

    int * ptr = array;

    int size1 = sizeof ( array ) / sizeof( int);
    int size2 = sizeof ( ptr ) / sizeof( int );

    Only size1 gives correct number of elements, not size2.

    How come size2 calculation does not work?
    Any thing I can do to make it work?

  2. #2
    Code Goddess Prelude's Avatar
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    >int size2 = sizeof ( ptr ) / sizeof( int );
    This is a trick we all wish would work. What is happening is the sizeof operator is getting the size of ptr, not the size of what ptr points to. Since a pointer is usually the size of an int, the result of the division should be 1. And no, dereferencing ptr wouldn't work either.

    -Prelude
    My best code is written with the delete key.

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