Array: Difference between revisions
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Array sizes are no longer always fixed at compile time: on entry to a subroutine or function it can declare an array of a size determined by that occasion (as in Algol since the 1960s), and arrays can be explicitly allocated and de-allocated storage according to program logic. But, their type and dimensionality remain fixed.
Arrays remain resolutely rectilinear in shape. There is no direct facility to enable "triangular" arrays, still less ragged arrays. Triangular (and potentially other shape) arrays can be attained with a little effort: most simply, use a rectilinear array and waste the unused portion, otherwise, use a one-dimensional array and calculate offsets into it. But it may be possible to employ ''two'' triangular arrays, that can be fitted into a rectilinear array, possibly with special treatment of the diagonal elements; if so, one must be rigorous about keeping track of which has what subscripts! Escalating to three (or more) dimensions is quite possible, but, a calm and resolute mind is
REAL, ALLOCATABLE:: COL(:)
END TYPE AROW
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