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--- el:function [2016/01/01 22:39]
+++ el:function [2020/02/28 10:46] (current)
@@ Line 1: / Line 1: @@
+===== Function =====
+==== Format ====
+**function** functionname ( //variable list// )\\
+//statements//\\
+**end function**
+**function** functionname$ ( //variable list// )\\
+//statements//\\
+**end function**
+==== Description ====
+Create a function that will receive zero or more values, process those values and return either a numeric or string value.  Return values are set by assigning the name of the function and executing a [[Return|Return]] statement or allowing the //End Function// statement to be executed.  All variables used within the function will be local to the function and will not change the values in the calling code.
+In many structured languages the return value of a function is set using the [[return|Return]] statement.  In BASIC-256 the returned value of a function is set by assigning the function name the value and either executing the [[Return|Return]] statement or reaching the end of the function.  A numeric function has the default return value of zero (0) and a string function has the default value of a zero length string ("").
+Subroutine variables may a list of zero or more, comma separated, numeric or string variables.  Arrays and variables may be passed by reference using the [[Ref|Ref]] definition.
+Functions should be defined at the bottom of your program, and can not be defined within another function, [[Subroutine|Subroutine]] or control block ([[if|If/Then]], [[do|Do/Until]], ...)
+==== Example ====
+<code>
+print double$("Hello")
+print triple(3)
+end
+function double$(a$)
+   double$ = a$ + a$
+end function
+function triple(b)
+   triple = b * 3
+   return
+   triple = 9999	# code never gets executed
+end function
+</code>
+will display\\
+<code>
+HelloHello
+</code>
+==== See Also ====
+{{page>en:start#Program Control&noheader}}
+==== New To Version ====
+.9.9.1

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