001C++程序设计2.ppt

* * 语句： if((C1 C2) || (C3 C4)) S1; else S2; 其中C1，C2，C3和C4是子句，S1和S2是语句。 子句覆盖要求测试数据能使四个从句C1,C2,C3和C 4都分别至少取一次true值和至少取一次false值。 子句覆盖 * * templateclass T int Max(T a[], int n) {// 寻找a [ 0 : n - 1 ]中的最大元素 int pos = 0; for (int i = 1; i n; i++) if (a[pos] a[i]) pos = i; return pos; } 数据集a[0:4]=[2,4,6,8,9]提供何种覆盖 ? 数据集a[0:4]=[4,2,6,8,9]提供何种覆盖 ? 程序1-31 寻找最大元素 * * Edsger Wybe Dijkstra(Algol60编译器设计者和实现者，THE操作系统的设计者,72年图灵奖): “编程的艺术是处理复杂性的技术”。 “测试只能证明错误的存在，不能证明错误不存在”。 关于测试 * * 测试能够发现程序中的错误。一旦测试过程中产生的结果与所期望的结果不同，就可以了解到程序中存在错误。 确定并纠正程序错误的过程被称为调试（debug）。 逻辑推理 程序跟踪 调试(debug) * * 参数传递 递归思想 测试调试 第一章总结 * The two most important concepts in object-oriented programming are the class and the object. In the broadest term, an object is a thing, both tangible and intangible, which we can imagine. A program written in object-oriented style will consist of interacting objects. For a program to maintain bank accounts for a bank, we may have many Account, Customer, Transaction, and ATM objects. An object is comprised of data and operations that manipulate these data. * * * This diagram shows three instances of the Employee class. Their names are Bill, Steve, and Andy. They are more commonly referred to as Employee objects. One key fact to remember: A class must be defined before you can create an instance (object) of the class. * Notice that the name of the message we send to an object or a class must be the same as the method’s name. Because they are the same, the message name is commonly omitted from the diagram as shown above. Because they are the same, the phrase “calling an object’s method” is synonymous to “sending a message to an object.” * The deposit method in the previous slide is an action-only method. It takes some action when called, but returns no answer back to the caller. The getMonthlyFee method above is a value-returning method. When called, it returns a value. A method can be both: executes an action and returns some value. * * 发送消息得到返回值 这个消息没有变量 Acco