debug_print statement

作者分享了完成SSD3课程中的debugDNASequence.java测验的经历,通过使用Eclipse的调试工具,尤其是StepInto功能,深入了解了程序的运行过程。同时也提到了使用打印语句进行调试的方法。
今天做了一个SSD 3 的quiz ---debug DNASequence.java 。just spend a whole morning!真可谓万事开头难!

虽然才初步了解了eclipse强大的Debugger 的功能,那个Step Into功能(执行程序的下一步)可让你看到程序执行的每一个步骤,现在就不用担心程序是如何运行的问题,多态的问题也可以进一步的了解Step Over的功能(执行源程序中中断的下一条语句)。
有点不爽就是,Step Into以后,就不能回到前一步。

回头看SSD3 教材,Multiple quiz 1 有如下一道题:


As an aid in debugging a program in Java, print statements may be used to display which of the following types of information?

[list]
[1]he names of methods being called
[2]The values of the parameters of a method
[3]The values of the instance variables of a class
[/list]



(a) I, II, and III
(b) I and III only
(c) I and II only
(d) II and III only

蒙对了,但是对Print Statement 不是很了解,网上的资料也很少。个人理解:打印状态
[list]
[*]The called methods
[*]The value of parameters
[*]The value of loop control variables
[*]The value of local variables
[*]The value of instance variables
[/list]
要是能打印每一个步骤的详细执行,那就牛逼,一看打印,就知道什么地方有Debug。

慢慢理解!what is PrintStatement~~how to use It?
1. The name of a Java source file (a) has no restrictions (b) must be the same as the class it defines, ignoring case (c) must use the extension .class (d) must be the same as the class it defines, respecting case 2. Which of the following statements is (are) true about the use of an asterisk (*) in a Java import statement? Ⅰ.It does not incur run-time overhead. Ⅱ.It can be used to import multiple packages with a single statement. Ⅲ.It can be used to import multiple classes with a single statement (a) I, II, and III (b) I and III only (c) I only (d) III only ..... 9. According to the Java code conventions, files that contain Java source code have the suffix _____, and compiled bytecode files have the suffix _____. (a) .class, .java (b) .class, .javac (c) .java, .class (d) .javac, .class 10. As an aid in debugging a program in Java, print statements may be used to display which of the following types of information? I. The names of methods being called II. The values of the parameters of a method Ⅲ. The values of the instance variables of a class (a) I and II only (b) I and III only (c) II and III only (d) I, II, and III 1. In a UML class diagram's representation of a class, the top, middle, and lower rectangular compartments respectively describe the _____ of the class. (a) name, attributes, and methods (b) name, methods, and constants (c) attributes, methods, and name (d) attributes, methods, and constants 2. UML class diagrams can describe which of the following? I. The internal structure of classes Ⅱ. Relationships between classes (a) I and II (b) II only (c) None (d) I only ....... 1.The term class variable is a synonym for (a) a private data field (b) a static data field (c) a read-only variable (d) an instance variable 2. Consider the following Java program segment. import java.io.*; public class Test { public Test( ) { System.out.println("default"); } public Test( int i ) { System.out.println("non-default"); } public static void main(String[] args) { Test t = new Test(2); } } ......... 9. When a subclass defines an instance method with the same return type and signature as a method in its parent, the parent's method is said to be (a) private (b) hidden (c) overloaded (d) overridden 10. Which is a Java access modifier used to designate that a particular data field will not be inherited by a subclass? (a) final (b) protected (c) private (d) default 1. Consider the following Java program segment. String[] str = {"Three","Two","One"}; for (int i = 0; i < str.length; ++i) { System.out.println(str[i]+"/"); } What will be output upon execution of the program segment? (a) Three/Two/One/ (b) Three,Two,One (c) One,Two,Three (d) One/Two/Three/ 2. Consider the following Java program segment. int[] arr; arr = new int[3]; arr[2]=19; arr[1]=17; arr[0]=15; Which of the following Java statements is syntactically correct and semantically identical to the program segment? (a) int[] arr= {15, 17, 19}; (b) int[3] arr = {15, 17, 19}; (c) int arr = {15, 17, 19}; (d) int arr[3]= {15, 17, 19}; ........ 2. Which of the following statements is (are) true about any abstract method in Java? I. It contains no definition. Ⅱ. It cannot be declared public. (a) I and II (b) I only (c) None (d) II only 3. Consider the following Java program fragment. public void drive(Vehicle v) { ... } ... drive(obj); The method call drive(obj) is valid if obj is which of the following? I. A descendent of class Vehicle II. An ancestor of class Vehicle Ⅲ. An object of class Vehicle (a) I and III only (b) I, II, and III (c) III only (d) II and III only .....
评论
成就一亿技术人!
拼手气红包6.0元
还能输入1000个字符
 
红包 添加红包
表情包 插入表情
 条评论被折叠 查看
添加红包

请填写红包祝福语或标题

红包个数最小为10个

红包金额最低5元

当前余额3.43前往充值 >
需支付:10.00
成就一亿技术人!
领取后你会自动成为博主和红包主的粉丝 规则
hope_wisdom
发出的红包
实付
使用余额支付
点击重新获取
扫码支付
钱包余额 0

抵扣说明:

1.余额是钱包充值的虚拟货币,按照1:1的比例进行支付金额的抵扣。
2.余额无法直接购买下载,可以购买VIP、付费专栏及课程。

余额充值