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Here, sizeof buffer is equivalent to 10 * sizeof buffer [0], which evaluates to 10, because the size of the type char is defined as 1. C99 adds support for flexible array members to structures. This form of array declaration is allowed as the last element in structures only, and differs from normal arrays in that no length is specified to the ...
Thus, if the array is seen as a function on a set of possible index combinations, it is the dimension of the space of which its domain is a discrete subset. Thus a one-dimensional array is a list of data, a two-dimensional array is a rectangle of data, [12] a three-dimensional array a block of data, etc.
For example, in the Pascal programming language, the declaration type MyTable = array [1.. 4, 1.. 2] of integer, defines a new array data type called MyTable. The declaration var A: MyTable then defines a variable A of that type, which is an aggregate of eight elements, each being an integer variable identified by two indices.
is how one would use Fortran to create arrays from the even and odd entries of an array. Another common use of vectorized indices is a filtering operation. Consider a clipping operation of a sine wave where amplitudes larger than 0.5 are to be set to 0.5. Using S-Lang, this can be done by y = sin(x); y[where(abs(y)>0.5)] = 0.5;
char * pc [10]; // array of 10 elements of 'pointer to char' char (* pa)[10]; // pointer to a 10-element array of char The element pc requires ten blocks of memory of the size of pointer to char (usually 40 or 80 bytes on common platforms), but element pa is only one pointer (size 4 or 8 bytes), and the data it refers to is an array of ten ...
C struct data types may end with a flexible array member [1] with no specified size: struct vectord { short len ; // there must be at least one other data member double arr []; // the flexible array member must be last // The compiler may reserve extra padding space here, like it can between struct members };
A = round (rand (3, 4, 5) * 10) % 3x4x5 three-dimensional or cubic array > A (:,:, 3) % 3x4 two-dimensional array along first and second dimensions ans = 8 3 5 7 8 9 1 4 4 4 2 5 > A (:, 2: 3, 3) % 3x2 two-dimensional array along first and second dimensions ans = 3 5 9 1 4 2 > A (2: end,:, 3) % 2x4 two-dimensional array using the 'end' keyword ...
More generally, there are d! possible orders for a given array, one for each permutation of dimensions (with row-major and column-order just 2 special cases), although the lists of stride values are not necessarily permutations of each other, e.g., in the 2-by-3 example above, the strides are (3,1) for row-major and (1,2) for column-major.