| Code | Type | Description |
| 10 | Documentation | comments |
| 20 | Syntax | spelling, punctuation |
| 30 | Build, Package | version control |
| 40 | Assignment | scope, duplicate names |
| 50 | Interface | I/O, user formats |
| 60 | Checking | error messages |
| 70 | Data | structure, content |
| 80 | Function | logic, pointers |
| 90 | System | configuration, timing |
| 100 | Environment | compile, other support |