如何在COBOL中根据库存总量添加对应数量的星号字符串？

Got it, let's tackle this COBOL problem. The goal is to generate the right number of asterisks based on inventory levels and append them to your output line. Here are a couple of clean, practical ways to implement this:

First, Set Up Your Working Storage #

Start by defining the necessary variables in your WORKING-STORAGE SECTION—these will hold your inventory count, the asterisk string, and your final output line:

WORKING-STORAGE SECTION.
01 WS-INVENTORY-TOTAL    PIC 9(3) VALUE 0.  *> Holds current inventory level
01 WS-ASTERISKS          PIC X(5) VALUE SPACES. *> Max 5 asterisks needed
01 WS-OUTPUT-LINE        PIC X(80) VALUE SPACES. *> Your output line (adjust length as needed)

Method 1: Use STRING with REPEAT (COBOL 85+) #

If your compiler supports COBOL 85 or later, the STRING statement's REPEAT option is the most concise way to generate repeated characters. Here's how it works:

PROCEDURE DIVISION.
    *> Example inventory value (replace with your actual inventory field)
    MOVE 42 TO WS-INVENTORY-TOTAL.

    *> Reset asterisk field to spaces first
    MOVE SPACES TO WS-ASTERISKS.

    *> Determine how many asterisks to generate
    IF WS-INVENTORY-TOTAL < 10
        STRING '*' REPEAT 5 TIMES DELIMITED BY SIZE
            INTO WS-ASTERISKS
    ELSE IF WS-INVENTORY-TOTAL < 50
        STRING '*' REPEAT 2 TIMES DELIMITED BY SIZE
            INTO WS-ASTERISKS
    END-IF.

    *> Append asterisks to your output line
    *> Use DELIMITED BY SPACE to capture only the populated part of your line
    STRING WS-OUTPUT-LINE DELIMITED BY SPACE,
           WS-ASTERISKS DELIMITED BY SIZE
           INTO WS-OUTPUT-LINE
    END-STRING.

    *> Print the final line
    DISPLAY WS-OUTPUT-LINE.

Why this works: #

The REPEAT keyword tells COBOL to repeat the '*' character the specified number of times, and DELIMITED BY SIZE ensures we fill the entire WS-ASTERISKS field (or as much as needed).

Method 2: Compatibility with Older COBOL Versions #

If you're working with a pre-COBOL 85 compiler that doesn't support REPEAT, use a pre-defined asterisk constant and substring it as needed:

WORKING-STORAGE SECTION.
*> Add a constant with the maximum number of asterisks we'll need
01 WS-FULL-ASTERISKS     PIC X(5) VALUE '*****'.
*> Keep the other variables from earlier
01 WS-INVENTORY-TOTAL    PIC 9(3) VALUE 0.
01 WS-ASTERISKS          PIC X(5) VALUE SPACES.
01 WS-OUTPUT-LINE        PIC X(80) VALUE SPACES.

PROCEDURE DIVISION.
    *> Example emergency inventory level
    MOVE 7 TO WS-INVENTORY-TOTAL.

    MOVE SPACES TO WS-ASTERISKS.
    IF WS-INVENTORY-TOTAL < 10
        *> Use all 5 asterisks
        MOVE WS-FULL-ASTERISKS TO WS-ASTERISKS
    ELSE IF WS-INVENTORY-TOTAL < 50
        *> Take the first 2 asterisks from the constant
        MOVE WS-FULL-ASTERISKS(1:2) TO WS-ASTERISKS
    END-IF.

    *> Append to output line (same as method 1)
    STRING WS-OUTPUT-LINE DELIMITED BY SPACE,
           WS-ASTERISKS DELIMITED BY SIZE
           INTO WS-OUTPUT-LINE
    END-STRING.

    DISPLAY WS-OUTPUT-LINE.

Alternative: Perform Loop (For Ultimate Compatibility) #

If you need to support extremely old compilers, you can use a PERFORM loop to build the asterisk string one character at a time:

WORKING-STORAGE SECTION.
01 WS-INVENTORY-TOTAL    PIC 9(3) VALUE 0.
01 WS-ASTERISKS          PIC X(5) VALUE SPACES.
01 WS-OUTPUT-LINE        PIC X(80) VALUE SPACES.
01 WS-COUNT              PIC 9(1) VALUE 0. *> Counter for the loop

PROCEDURE DIVISION.
    MOVE 35 TO WS-INVENTORY-TOTAL.

    MOVE SPACES TO WS-ASTERISKS.
    IF WS-INVENTORY-TOTAL < 10
        PERFORM VARYING WS-COUNT FROM 1 BY 1 UNTIL WS-COUNT > 5
            MOVE '*' TO WS-ASTERISKS(WS-COUNT:1)
        END-PERFORM
    ELSE IF WS-INVENTORY-TOTAL < 50
        PERFORM VARYING WS-COUNT FROM 1 BY 1 UNTIL WS-COUNT > 2
            MOVE '*' TO WS-ASTERISKS(WS-COUNT:1)
        END-PERFORM
    END-IF.

    *> Append to output line
    STRING WS-OUTPUT-LINE DELIMITED BY SPACE,
           WS-ASTERISKS DELIMITED BY SIZE
           INTO WS-OUTPUT-LINE
    END-STRING.

    DISPLAY WS-OUTPUT-LINE.

This is more verbose, but it works on virtually any COBOL compiler.

Pro Tip for Fixed-Length Output Lines #

If your output line is a fixed length (like 80 characters), you can skip the STRING step and directly place the asterisks at the end of the line:

*> For an 80-character line, positions 76-80 are the last 5 characters
MOVE WS-ASTERISKS TO WS-OUTPUT-LINE(76:5)

This is faster and avoids any issues with DELIMITED BY SPACE if your line has embedded spaces.

内容的提问来源于stack exchange，提问作者becca