Origin of pointer syntax

This is a discussion on Origin of pointer syntax within the C++ Programming forums, part of the General Programming Boards category; I've always been curious why you declare a pointer like this: Code: aType * ptr; you ask for a reference ...

  1. #1
    Use this: dudeomanodude's Avatar
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    Origin of pointer syntax

    I've always been curious why you declare a pointer like this:
    Code:
    aType * ptr;
    you ask for a reference like this:
    Code:
    &something; // give me a reference to something
    and you dereference with the same thing you declare a pointer with:
    Code:
    *something; // give me the value of something
    Why is that? What is the commonality between declaring a pointer and dereferencing it?
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    Captain Crash brewbuck's Avatar
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    Quote Originally Posted by dudeomanodude View Post
    Why is that? What is the commonality between declaring a pointer and dereferencing it?
    Compare these two declarations:

    Code:
    int x;
    int *y;
    The first one says, "x is an integer." The second one, although technically declaring a pointer, can be thought of as saying, "*y is an integer." Therefore, y must be "something" which, when you stick a star on the front of it, is an integer. In other words, a pointer to an integer.

    So the declaration syntax is borrowing from the dereferencing syntax, not the other way around.

  3. #3
    and the Hat of Guessing tabstop's Avatar
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    So if you have
    Code:
    int * ptr;
    then ptr is a pointer-to-int and *ptr is an int, all at the same time.

    IOW, they needed something in the declaration to say "this is a pointer", and using the same symbol * as dereferencing allowed the pun above, without using up another keyword or symbol.

    (I seem to recall somebody smart and important saying much the same thing but with more authority -- maybe Stroustrup in his FAQ?)

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    Use this: dudeomanodude's Avatar
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    Quote Originally Posted by brewbuck View Post
    The second one, although technically declaring a pointer, can be thought of as saying, "*y is an integer."

    So the declaration syntax is borrowing from the dereferencing syntax, not the other way around.
    Yep, that clears it up for me.

    Thanx.
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