SIZE ( array [{% | $}] ) or

SIZE ( variable [{% | $}] ) or

SIZE ( value)


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 any value or 0 if it does not, ie. if PRINT variable would show an asterisk to show that variable is not yet defined. Note that even though on SMS an unset variable does not show an asterisk when you use PRINT variable, this does not prevent this function from returning the correct value.

The return for a constant parameter such as:




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, for example:

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, eg. for DIM a$(2,2), SIZE(a$) will not give 3*3 = 9 but 3.

Generally the return value of SIZE does not depend on the actual contents of the passed object. SIZE recognises if part of an object (especially strings and arrays) was passed.


DIM numbers(1,2,3,4,5)
PRINT SIZE(numbers)

returns 2*3*4*5*6=720.

yippie$="what a wonderful world"
PRINT SIZE(yippie$)

returns 1.


returns 0

DIM string$(12,7,10)
PRINT SIZE(string$)

returns 13*8=104

PRINT SIZE(string$(1 TO))

returns 12*8=96.


String arrays also contain numeric values - the first element (which is character zero) of a string contains the size of the string. For instance, take the above string$ array and then enter:

string$(4,4) = "knocking"


PRINT string$(4,4)

and you will see ‘knocking’ in #1.

PRINT string$(4,4,5)

gives the fifth character of knocking, the k, and:

PRINT string$(4,4,1)

the first one, again a k. And:

PRINT string$(4,4,0)

There is no character before the first, instead you will get the integer number 8 because:


This is tricky and not really necessary to know about as you can use LEN… just in case you come across the phenomenon and have wondered about it. See also DIM for a further explanation of strings.


Before v2.06, this function may refuse to work on some implementations, giving ‘Bad Parameter’ error or returning the wrong value for string arrays.


If the parameter is a single dimension string array, for example:

DIM a$(10)

the value returned is 0. It is hoped that this will be fixed in a future version so that the value returned is 1.


DIMN and NDIM return other information about an array, eg: PRINT SIZE(a$) * DIMN(a$,NDIM(a$)) gives the total number of characters which can be stored in a string array a$. LEN returns the length of a string. FREE_MEM allows you to check how much memory an array uses.