Base Class Library, Arrays, Queues and Stacks

spgennard — Thu, 19 Nov 2009 21:41:27 +0000

Continuing the series of blogs about COBOL and the .Net base class library…

The .Net base class library has a wealth classes and an huge of amount of methods/properties.

The .Net base class library has a key handy namespace that contains are the lovely classes, which is System.Collections.

As you can see from the above link, it does have quite a lot, so for this blob entry I will look at:

arrays of numbers

queues

stacks

Lets start the first example by using an array of numbers… just to demonstrate its not just strings you can assign to the arrays using “values”.

01 numbers binary-long occurs 10
values 10 20 30 40 50 10 20 30 40 50.

01 num binary-long value 0.
01 average binary-double value 0.

procedure division.
perform varying num through numbers
add num to average
end-perform
divide average by numbers::"Length" giving average
display "Average is : " average

Running the above code gives us:

Average is : +00000000000000000030

The next class that is helpful, is the Queue class, this allows us to “Enqueue” and “Dequeue” item using the same methods, the queue is again displayed using the “perform through” syntax.

$set ilusing"System"
$set ilusing"System.Collections"

01 alphabetQueue type "Queue".
01 item object reference.

set alphabetQueue to new type "Queue"()
invoke alphabetQueue::"Enqueue"("A item")
invoke alphabetQueue::"Enqueue"("B item")
invoke alphabetQueue::"Enqueue"("C item")

display "The initial queue is: "
perform varying item through alphabetQueue
display " " item
end-perform

display "".
display "De-Queue an item: " alphabetQueue::"Dequeue"()

display "".
display "Afterwards is: "
perform varying item through alphabetQueue
display " " item
end-perform

Running the above queue example gives:

The initial queue is:
A item
B item
C item

De-Queue an item: A item

Afterwards is:
B item
C item

Next, lets look at the ‘Stack’ class, this is very similar, expect it uses the “Push”, “Pop” methods and we iterate through the Stack using the ‘perform through’ syntax.

$set ilusing"System"
$set ilusing"System.Collections"

01 alphabetStack type "Stack".
01 item object reference.

set alphabetStack to new type "Stack"()
invoke alphabetStack::"Push"("A item")
invoke alphabetStack::"Push"("B item")
invoke alphabetStack::"Push"("C item")

display "The initial stack is: "
perform varying item through alphabetStack
display " " item
end-perform

display "".
display "Pop item: " alphabetStack::"Pop"()

display "".
display "Afterwards is: "
perform varying item through alphabetStack
display " " item
end-perform

Running the above stack example gives:

The initial stack is:
C item
B item
A item

De-Stack an item: C item

Afterwards is:
B item
A item

As you can see using the base class library collection classes with COBOL is just as easy as using C#… so if you are already using COBOL… continue and try out the .Net base class library.. it really is very easy to use and it will make you more productive.. so please explore and enjoy .Net and its Base Class library.

Too Iterate or not…

spgennard — Tue, 10 Nov 2009 20:51:06 +0000

Over the next couple of weeks, I will explore some of the reasons why I think managed environments are good for COBOL.

So.. lets the show on the road…

Setting up arrays/occurs items in COBOL and manipulating them can be painful. Lets look at some traditional code for playing around with a “months” table.

01 month-val.
05 FILLER PIC X(10) value "January".
05 FILLER PIC X(10) value "February".
05 FILLER PIC X(10) value "March".
05 FILLER PIC X(10) value "April".
05 FILLER PIC X(10) value "May".
05 FILLER PIC X(10) value "June".
05 FILLER PIC X(10) value "July".
05 FILLER PIC X(10) value "August".
05 FILLER PIC X(10) value "September".
05 FILLER PIC X(10) value "October".
05 FILLER PIC X(10) value "November".
05 FILLER PIC X(10) value "December".

01 month-tab redefines month-val.
05 months occurs 12 times.
10 month-NAME PIC X(10).

01 month PIC 99.

01 secondQuarterMonths pic x(70).

display "The months are:"
perform varying month from 1 by 1 until month equals 12
display " " months(month)
end-perform

display " "
display "The second quarter months are: "

string months(4) delimited by space
"/" delimited by size
months(5) delimited by space
"/" delimited by size
months(6) delimited by space
into secondQuarterMonths
on overflow
display "FATAL Error - secondQuarterMonths is too small"
stop run
end-string

display " " secondQuarterMonths

Now, imagine we can use one or two of the .Net’s base class libraries combined with some nifty natural extensions to COBOL to do some of the heavy lifting.

Defining the month item as a native .Net type ie: a string combined with using the base class libraries Split methods allows us to setup a array quickly.

01 commaDelimited string value
"January,February,March,April,May,June,July,August," &
"September,October,November,December".

01 months string occurs any.
01 month string.

01 secondQuarterMonths string.

set months to commaDelimited::"Split"(',')

display "The months are: "
perform varying month through months
display " " month
end-perform

display " "
display "The second quarter months are: "

set secondQuarterMonths to type "System.String"::"Join"('/', months, 3, 3)

display " " secondQuarterMonths

The .Net version, besides being smaller feels much easier to read, especially if you have any exposure to the .Net base class library from other languages such as C# or VB.Net.

Of course in a real world example, we don’t need to use the split method to setup an array, we could just use the “values” clause… for example:

01 months string occurs 12 values
"January" "February" "March" "April" "May" "June"
"July" "August" "September" "October" "November" "December".

01 month string.

perform varying month through months
display month
end-perform

If however you don’t want to hardcode the months, you can always use: CultureInfo.CurrentCulture.DateTimeFormat.GetMonthName() in the System.Globalization namespace.

So… lets just do it…

01 Months string occurs any.
01 Month string.

set Months to type "System.Globalization.DateTimeFormatInfo"::
"CurrentInfo"::"MonthNames"

perform varying Month through Months
display Month
end-perform

Now, I hope you feel like I do that COBOL and .Net are indeed perfect partners to each other.

The above COBOL .Net code will execute on Micro Focus Net Express and I suspect it will also work on Fujitsu’s netCobol too.

The ramblings of a yorkshire tyke » BaseCL

Base Class Library, Arrays, Queues and Stacks

Too Iterate or not…