Описание тега allocatable-array
This tag is about the use of allocatable arrays in Fortran. Such arrays can have their bounds (shape) varying at run time. Questions using this tag should usually have the more general fortran tag also.
In Fortran, the bounds (and shape) of an allocatable array are determined when it is allocated. Subsequent redefinition or undefinition of any entities in the bound expressions does not affect the array specification.
If the lower bound is greater than the upper bound, that dimension has an extent of zero, and the array has a size of zero. If the lower bound is omitted, it is assumed to be 1.
When an array is allocated, it is definable. If you try to allocate a currently allocated allocatable array, an error occurs.