Defining Pictures
So far, you've defined small variables, but you also can define longer ones in COBOL. Numeric variables can be as large as 18 digits:
01 THE-NUMBER PICTURE IS 999999999999999999.
Numeric variables are limited to 18 digits, but the length of alphanumeric variables is limited by the version of COBOL that you have. LPI COBOL has a limit of 32,767 characters. ACUCOBOL has a limit of 65,520 characters. The Professional Micro Focus COBOL compiler (big brother to Micro Focus Personal COBOL) has a limit of a whopping 256 million characters.
Defining long variables could become a tedious task if every X and 9 had to be spelled out explicitly; and typing in long strings of X or 9 could result in errors. In addition, having to type PICTURE IS for every variable can get tiring in large programs. Fortunately, COBOL allows some abbreviations that make the task less cumbersome.
The word IS in PICTURE IS is optional, and the word PICTURE can be abbreviated as PIC. This abbreviation is used so commonly that it is rare to see a program containing PICTURE IS:
01 THE-MESSAGE PIC XXXXXX.
The second abbreviation is even more useful. The picture itself can be abbreviated by typing one picture character followed by the number of repetitions of that character in parentheses. Thus, PIC XXXXXX becomes PIC X(6), and PIC 99999 becomes PIC 9(5). The 18-digit number shown earlier becomes the following:
01 THE-NUMBER PIC 9(18).
This works even when the repetition is one, so it is possible to describe PIC X as PIC X(1). When you are reading a listing, it sometimes is easier to determine the size of a variable quickly by scanning the values in parentheses. Some programmers make it a practice always to include the size in parentheses.
If you want to use the abbreviations to cut down on keystrokes, abbreviate anything exceeding a length of four. PIC XXXX and PIC X(4) require the same number of keystrokes, so for the sake of typing speed, it doesn't matter which you use. PIC X is faster to type than PIC X(1), but PIC X(5) is faster to type than PIC XXXXX.
You might find the use of parentheses is dictated by the style manual of the company that is using the program. If it is for your own use, pick the one that is more comfortable for you.
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