cobol-java-v3/benchmark-programs/25-subprogram/README.md

25-subprogram

电信业务场景

计费子程序。通过CALL语句调用计费计算子程序，传入用量和单价参数，返回计费金额。演示USING参数传递和RETURN-CODE使用。

Purpose

Tests COBOL subprogram calling conventions including CALL with literal names, CALL with variable program names, and CALL with IS INITIAL.

Architecture

• callee.cbl — Subprogram (PROGRAM-ID. callee) that adds two numbers via LINKAGE SECTION parameters and tracks first-call state.
• caller.cbl — Main program (PROGRAM-ID. caller) with three test cases.

Tests

1. CALL literal: CALL "callee" USING 100 200 -> expects 300
2. CALL variable: CALL WS-PGM-NAME USING 10 20 -> expects 30
3. CALL IS INITIAL: CALL "callee" IS INITIAL USING 1 2 -> expects 3, forces subprogram reinitialization

Key Techniques

• CALL USING for parameter passing
• LINKAGE SECTION for parameter definitions
• GOBACK to return to caller
• RETURN-CODE for status communication
• IS INITIAL to reinitialize subprogram state