>>SOURCE FORMAT IS FREE
*> cobol-compute-rounded.cob - COMPUTE with and without
*>   ROUNDED, ROUNDED MODE IS NEAREST-EVEN, an overflow trapped by
*>   ON SIZE ERROR, the same overflow untrapped, and a divide by zero
*> Dialect: GnuCOBOL 3.x, free format
*> Status : desk-checked against the GnuCOBOL 3.2 Programmer's Guide;
*>          compiled and run with GnuCOBOL 3.2 on 2026-10-29
*> Inputs : none
*> Outputs: nine lines on standard output
*> Build  : cobc -x cobol-compute-rounded.cob
*> Run    : ./cobol-compute-rounded
*>          (Windows: cobol-compute-rounded.exe)

IDENTIFICATION DIVISION.
PROGRAM-ID. COMPUTE-DEMO.

ENVIRONMENT DIVISION.

DATA DIVISION.
WORKING-STORAGE SECTION.
01 WS-Price          PIC 9(3)V99  VALUE 19.99.
01 WS-Qty            PIC 9(3)     VALUE 3.
01 WS-Tax-Rate       PIC V999     VALUE 0.075.
01 WS-Total-Trunc    PIC 9(5)V99.
01 WS-Total-Round    PIC 9(5)V99.

01 WS-In-A           PIC 9V999    VALUE 2.345.
01 WS-In-B           PIC 9V999    VALUE 2.355.
01 WS-Out-Default    PIC 9V99.
01 WS-Out-Even       PIC 9V99.

01 WS-Small          PIC 9(3)     VALUE 5.
01 WS-Big            PIC 9(5)     VALUE 12345.
01 WS-Divisor        PIC 9        VALUE 0.
01 WS-Result         PIC 9(5)V99  VALUE 0.

PROCEDURE DIVISION.
MAIN-PARAGRAPH.
*>  1. The same expression, truncated and rounded.
    COMPUTE WS-Total-Trunc = WS-Price * WS-Qty * (1 + WS-Tax-Rate)
    COMPUTE WS-Total-Round ROUNDED
                         = WS-Price * WS-Qty * (1 + WS-Tax-Rate)
    DISPLAY "Total, no ROUNDED   : " WS-Total-Trunc
    DISPLAY "Total, ROUNDED      : " WS-Total-Round

*>  2. Rounding modes on a tie: 2.345 and 2.355 into two decimals.
    COMPUTE WS-Out-Default ROUNDED = WS-In-A
    COMPUTE WS-Out-Even ROUNDED MODE IS NEAREST-EVEN = WS-In-A
    DISPLAY "2.345 default mode  : " WS-Out-Default
    DISPLAY "2.345 NEAREST-EVEN  : " WS-Out-Even
    COMPUTE WS-Out-Default ROUNDED = WS-In-B
    COMPUTE WS-Out-Even ROUNDED MODE IS NEAREST-EVEN = WS-In-B
    DISPLAY "2.355 default mode  : " WS-Out-Default
    DISPLAY "2.355 NEAREST-EVEN  : " WS-Out-Even

*>  3. Overflow trapped: the receiver keeps its old value.
    COMPUTE WS-Small = WS-Big
        ON SIZE ERROR
            DISPLAY "Size error trapped, WS-Small still " WS-Small
        NOT ON SIZE ERROR
            DISPLAY "No size error, WS-Small now " WS-Small
    END-COMPUTE

*>  4. The same overflow untrapped: leading digits vanish silently.
    COMPUTE WS-Small = WS-Big
    DISPLAY "Untrapped overflow, WS-Small now " WS-Small

*>  5. Division by zero, trapped instead of aborting the run.
    COMPUTE WS-Result = WS-Price / WS-Divisor
        ON SIZE ERROR
            DISPLAY "Divide by zero trapped, WS-Result still " WS-Result
    END-COMPUTE
    STOP RUN.