作业3.2：psp
| PSP2.1 | Personal Software Process Stages | Time |
| Planning | 计划 | 20min |
| Estimate | 估计这个任务需要多长时间 | 3.5h |
| Development | 开发 | 10min |
| Analysis | 需求分析 | 15min |
| Design Spec | 生成设计文档 | 40min |
| Design Review | 设计复审 | 10min |
| Coding Standard | 代码规范 | 5min |
| Design | 具体设计 | 1.5h |
| Coding | 具体编码 | 1h |
| Code Review | 代码复审 | 15min |
| Test | 测试 | 10min |
| Reporting | 报告 | 20min |
| Postmortem&Report | 总结和报告 | 20min |
