作者在软件开发过程中，体会到使用断言技术对提高软件的质量大有帮助，特别是采用契约式编程(Programming By Contract)的软件。同时各类调试子系统，如调试信息输出系统、内存管理调试系统等，也是软件开发中的重要工具。
双语例句
1
Design byContract, or programmingbyContract, is not a new concept in programming, many languages already having such implementations.
契约式设计(或“契约式编程”)并不是编程领域的新概念，许多语言中已经有类似的实现了。
2
It also explains the difference between programmingbycontract and defensive programming with a clever situation where your customers request that the framework code do the checking.