Specifications

[ 3 ] User-defined Functions

Before calling user-defined functions, it is necessary to define those functions with any of the

following statements. Generally, those statements should be placed before the main routine

starts.

DEF FN (in single-line form)

DEF FN...END DEF (in block form)

SUB...END SUB

FUNCTION...END FUNCTION

When using SUB and FUNCTION functions written in other files, it is necessary to declare

them with the

DECLARE statement before calling them.

[ 4 ] Block-structured Statements

The statements listed below have the statement block structure and are useful for structured

programming.

FOR...NEXT

IF...THEN...ELSE...END IF

SELECT...CASE...END SELECT

WHILE...WEND

■ Nested Structure

Block-structured statements allow you to write nesting programs as shown below.

FOR i=1 TO 10

FOR j=2 TO 10 STEP 2

PRINT i, j, k

NEXT j

NEXT i

Nesting subroutines as shown below is also possible.

GOSUB aaa

aaa

PRINT "aaa"

GOSUB bbb

RETURN

bbb

PRINT "bbb"

RETURN