SIZE

Syntax: SIZE ( array [{% | $}] )     
    or: SIZE ( variable [{% | $}] )
    or: SIZE ( value)
Location: Math Package

The function SIZE can take any kind of variable, array or constant. The returned value depends very much on the type of parameter:

If a simple variable was passed, the function returns either 0 or 1, 1 if the variable points to a value or 0 if it does not.

The return for a constant parameter such as: PRINT SIZE(-22.3) or PRINT SIZE("QL") is always 1. 

The return for arrays is entirely different. 

Passing an array tells SIZE to count its elements. Note the existence of a zero element, eg. DIM a(2,2) gives a nine elements in all:
  
a(0,0), a(0,1), a(0,2)
a(1,0), a(1,1), a(1,2)
a(2,0), a(2,1), a(2,2)

SIZE handles string arrays differently in that it returns the number of strings, not the number of characters.

CROSS-REFERENCE:
DIMN and NDIM return other information about an array.
LEN returns the length of a string. 
FREE_MEM allows you to check how much memory an array uses.
