The Clockwise/Spiral Rule of C declarations

Re:The Clockwise/Spiral Rule of C declarations by rfw on Sunday October 23, 2016 @07:02PM (#12775845)

The rule is misleading in cases like:

    int* arr[][10];

Spiral rule would state "arr is an array of pointers to arrays of 10 ints", where actually it would be "arr is an array of array of 10 pointers to int".

Instead, when you write declarations, do it from right-to-left, e.g.:

   char const* argv[];

"argv is an array of pointers to constant characters"

It doesn't help with reading, unfortunately.

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Re:The Clockwise/Spiral Rule of C declarations by clusmore on Sunday October 23, 2016 @07:18PM (#12775902)

I think the advice that helped me the most was "Declaration follows usage".

  int* arr[][10];

If you index twice into arr and then dereference, you'll get an int. So arr must be an array of array of pointer to int.

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Re:The Clockwise/Spiral Rule of C declarations by convales on Sunday October 23, 2016 @07:23PM (#12775916)

Declaration follows usage is much more easier to follow than the artificial spiral rules, IMHO with a few typedefs the declaration follows usage can make things pretty simple.

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Re:The Clockwise/Spiral Rule of C declarations by dllthomas on Monday October 24, 2016 @06:15AM (#12777711)

To my mind that's one part of the reason the * belongs next to arr rather than next to int.

The other part is `int* x, y`.

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Re:The Clockwise/Spiral Rule of C declarations by vostok on Sunday October 23, 2016 @07:22PM (#12775913)

For this reason I strongly prefer writing

    char const

rather than

    const char

Is there a reason to prefer the second version? It's a lot more popular in my experience.

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Re:The Clockwise/Spiral Rule of C declarations by Spivak on Sunday October 23, 2016 @07:57PM (#12776020)

It's the difference between "declare a constant integer" and "declare an integer constant" and to me the former more accurately represents what you're doing since `const` is modifying `int`, `int` isn't modifying `const`.

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Re:The Clockwise/Spiral Rule of C declarations by kccqzy on Sunday October 23, 2016 @08:36PM (#12776132)

Putting const on the right makes more sense when you have pointers or references. Then you just always read from right to left: `int const ` is a pointer to constant integer whereas `int const` is a constant pointer to integer.

Also your argument about which modifies which is strongly anglocentric: there are plenty of people whose native language puts modifiers after the things they modify.

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