Sort an array
Array_Type array_sort (Array_Type a, String_Type f)
array_sort sorts the array a into ascending order
according to the function specified by the name f and returns
an integer array that represents the result of the sort.
The sort function represented by f must be a S-lang
user-defined function that takes two arguments. The function must
return an integer that is less than zero if the first parameter is
considered to be less than the second, zero if they are equal, and a
value greater than zero if the first is greater than the second.
The integer array returned by this function is simply an index that
indicates the order of the sorted array. The input array a is
not changed.
An array of strings may be sorted using the strcmp function
since it fits the specification for the sorting function described
above:
variable A = String_Type [3];
A[0] = "gamma"; A[1] = "alpha"; A[2] = "beta";
variable I = array_sort (A, "strcmp");
array_sort has executed, the variable I will
have the values [2, 0, 1]. This array can be used to
re-shuffle the elements of A into the sorted order via the
array index expression A = A[I].
The current sorting algorithm is a heap-sort.
strcmp