typedef array with multiple arrays

Question

I want to be able to do this:

typedef int a[2], b[2], c[2];

without having to type the [2]. One solution is to do:

typedef struct { int a[2] } a, b, c;

but then you have to always do stuff like a.a[0] and that's no good.

So you're asking for advanced solution? Or determined to be able to do this? — Taha Tekdoğan
– Taha Tekdoğan, Commented May 21, 2016 at 17:24
a) I don't get why you are doing this. b) Chose C or C++, they have quite different type aliasing rules. — Baum mit Augen
– Baum mit Augen ♦, Commented May 21, 2016 at 17:26
Is this different than a 2 dimensional array: int f[3][2]? With indices matching the variables, such as a==f[0][x] and b==f[1][x] and c==f[2][x]? — Thomas Matthews
– Thomas Matthews, Commented May 21, 2016 at 17:36
Do you want the syntax for a typedef for an array of 2 integers? — Thomas Matthews
– Thomas Matthews, Commented May 21, 2016 at 17:37

Martin Bonner supports Monica · Accepted Answer · 2016-05-21 17:37:11Z

4

For C or C++98, a simple typedef will do:

typedef int int2[2];
int2 a, b, c;

answered May 21, 2016 at 17:37

Martin Bonner supports Monica

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Rames · Accepted Answer · 2016-05-21 17:28:30Z

4

Well, the question is tagged with C++ and C, but there is a simple C++11 solution:

using int_arr = int[2];
int_arr a, b, c;

answered May 21, 2016 at 17:28

Rames

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SkyWalker · Accepted Answer · 2016-05-23 07:50:22Z

1

I would rather define a more reusable type and SIMD friendly i.e.

template<typename T, int size>
struct type_t {
    // 32-byte AVX aligned ready for [gnu] auto-vectorization 
    typedef T array_t[size] __attribute__((aligned(32)));
};

typedef type_t<int, 2>::array_t int_array2;
typedef type_t<double, 2>::array_t double_array2;

// and then
int_array2 a, b, c;
double_array2 d, e, f;

edited May 23, 2016 at 7:50

answered May 21, 2016 at 20:49

SkyWalker

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