# 30-keybreak-other — Key Break Non-Summary Change Detector

## 电信业务场景

通话状态变化检测。对已排序的通话状态记录进行key切变化检测，当通话状态(待接听/通话中/已结束)发生变化时输出标记行。

Detects key changes without aggregation:

- Compare WS-PREV-KEY to detect key changes in sorted input
- On key change: write "*** KEY CHANGE TO: <KEY> ***" marker line
- No aggregation — every data record is written to output unchanged
- First record always starts with a marker line

## Files

| File | Purpose |
|------|---------|
| `main-30-keybreak-other.cbl` | COBOL program (fixed format) |
| `data-gen.sh` | Generate sorted test data (4 groups) |
| `run.sh` | Compile, run, display output |

## Input Record

| Field | Type | Length |
|-------|------|--------|
| KEY | PIC X | 10 |
| DATA | PIC X | 30 |

## Output

Data records written as-is, with marker lines inserted before
each new key group. Single-record groups produce a marker
followed immediately by the data record.