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Rexx - Subroutines
Rexx - Subroutines
In any programming language, the entire program is broken into logical modules. This makes it easier to write code that can be maintained easily. This is a basic requirement for any programming language.
In Rexx, modules can be written using Subroutines and functions. Let’s look at the subroutines in detail.
Defining a Subroutine
The syntax of a function declaration is as follows −
FunctionName: Statement#1 Statement#2 …. Statement#N
Where,
FunctionName − This is the name assigned to the subroutine.
Statement#1 .. Statement#N − These are the pst of statements that make up the subroutine.
The following program is a simple example showing the use of subroutines.
/* Main program */ call add exit add: a = 5 b = 10 c = a + b say c
The following things should be noted about the above program −
We are defining a subroutine called add.
The subroutine does a simple add functionapty.
The exit statement has to be used to signify the end of the main program.
The output of the above program would be as follows −
15
Working with Arguments
It is also possible to work with arguments in Rexx. The following example shows how this can be achieved.
/* Main program */ call add 1,2 exit add: PARSE ARG a,b c = a + b say c
The following things should be noted about the above program −
We are defining a subroutine called add which takes on 2 parameters.
In the subroutines, the 2 parameters are parsed using the PARSE and ARG keyword.
The output of the above program would be as follows −
3
Different Methods for Arguments
Let’s look at some other methods available for arguments.
arg
This method is used to return the number of arguments defined for the subroutine.
Syntax −
arg()
Parameters − None
Return Value − This method returns the number of arguments defined for the subroutine.
Example −
/* Main program */ call add 1,2 exit add: PARSE ARG a,b say arg() c = a + b say c
When we run the above program we will get the following result.
2 3
arg(index)
This method is used to return the value of the argument at the specific position.
Syntax −
arg(index)
Parameters
Index − Index position of the argument to be returned.
Return Value − This method returns the value of the argument at the specific position.
Example −
/* Main program */ call add 1,2 exit add: PARSE ARG a,b say arg(1) c = a + b say c
When we run the above program we will get the following result.
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