摘要：
Motivation 动机 All the time we design a program module and we create some class hierarchies. Then we extend some classes creating some derived classes. 阅读全文
摘要：
Motivation 动机 In this context, a responsibility is considered to be one reason to change. This principle states that if we have 2 reasons to change fo 阅读全文
摘要：
Motivation 动机 When we design an application we should take care how we are going to make abstract a module which contains several submodules. Consider 阅读全文
摘要：
Motivation 动机 When we design software applications we can consider the low level classes the classes which implement basic and primary operations(disk 阅读全文
摘要：
Motivation 动机 A clever application design and the code writing part should take care of the frequent changes that are done during the development and 阅读全文