Java复习题阅读程序题(27页).doc

-JAVA程序设计复习题之（三）阅读程序题（通信工程专业使用）三、阅读程序题。1、阅读以下程序：public class Sum public static void main( String args) double sum = 0.0 ; for ( int i = 1; i<= 100; i + ) sum += i;, System.out.println( "sum=" + sum ); 该程序完成的功能是： 求sum=1+2+3+.+100的和。2、阅读以下程序：public class Sum public static void main(String args) double sum = 0.0：for (int i=1; i<=100; i+)sum += i*i；System.out.println( "sum="+sum); 该程序的功能是： 求出sum的值为1到100的平方和。3、阅读以下程序：public class Sum public static void main(String args) double sum = 0.0；for(int i = 1; i <= 100; i+)sum += i*i*i;System.out.println("sum=" + sum); 此程序完成的功能是： 计算并输出1到100的立方和sum值。4、阅读以下程序：public class Sum public static void main(String args) double sum = 0.0；for (int i=1; i<=100; i+) sum += 1.0 / (double)i;System.out.println("sum="+sum); 此程序完成的功能是： 求解sum=1+1/2+1/3+.+1/100的值并打印输出。5、阅读以下程序import java.io.* ;public class Test public static void main(String args ) int i, s = 0;int a = 10, 20, 30, 40, 50, 60, 70, 80, 90;for ( i = 0 ; i < a.length; i+ )if(ai % 3 = 0) s += ai;System.out.println("s=" + s);请写出此程序的输出结果： s=1806、阅读以下程序 import java.io.*;public class abc public static void main(String args ) AB s = new AB("Great!","I love Eclipse."); System.out.println(s.toString( ); class AB String s1; String s2; public AB(String str1, String str2) s1 = str1; s2 = str2; public String toString( ) return s1 + s2;运行结果是： 运行结果是：Great! I love Eclipse.7、阅读以下程序import java.io.* ; public class abc public static void main(String args ) int i, s = 0 ; int a = 10 , 20 , 30 , 40 , 50 , 60 , 70 , 80 , 90 ; for ( i = 0 ; i < a.length ; i + ) if ( ai%3 = = 0 ) s += ai ; System.out.println("s="+s); 运行结果是： 运行结果：s = 1808、阅读以下程序import java.io.* ; public class abc public static void main(String args ) System.out.println("a=" + a + "nb=" + b); class SubClass extends SuperClass int c; SubClass(int aa, int bb, int cc) super(aa, bb); c = cc; class SubSubClass extends SubClass int a; SubSubClass(int aa, int bb, int cc) super(aa, bb, cc); A = aa + bb + cc; void show( )System.out.println("a="+a+"nb="+b+"nc="+c); 运行结果是： 运行结果：a=60b=20c=309、以下程序的输出结果为 相等 。class StringTest1 public static void main(String args) String s1="hello"String s2=new String("hello");if( s1.equals(s2) ) System.out.println("相等");else System.out.println("不相等");10、以下程序段的输出结果为 5 6 7 8 9 。public class TestArray public static void main(String args ) int i , j ;int a = 5,9,6,8,7; for ( i = 0 ; i < a.length-1; i + ) int k = i; for ( j = i ; j < a.length; j+ ) if ( aj < ak ) k = j; int temp = ai; ai = ak; ak = temp; for ( i =0 ; i<a.length; i+ ) System.out.print(ai+" "); System.out.println( ); 11、写出以下程序的功能。import java.io.*;public class TestFile public static void main(String args) throws Exception BufferedReader br = new BufferedReader(new InputStreamReader(System.in); BufferedWriter bw = new BufferedWriter(new FileWriter(“input.txt"); String s; while (true) System.out.print("请输入一个字符串： "); System.out.flush( ); s = br.readLine( ); if (s.length() = 0) break; bw.write(s); bw.newLine(); bw.close( ); 程序功能是： 程序功能是：从键盘逐一输入字符串，逐一输出至input.txt文件中，直至输入空行。12、阅读以下程序，写出输出结果。class Animal Animal( ) System.out.print ("Animal "); public class Dog extends Animal Dog( ) System.out.print ("Dog "); public static void main(String args) Dog snoppy = new Dog(); 输出结果是： 输出结果是：Animal Dog13、以下程序的输出结果为 Peter is 17 years old! 。public class Person String name;int age;public Person(String name, int age) this.name = name;this.age = age;public static void main(String args) Person c = new Person("Peter", 17);System.out.println(c.name + " is " + c.age + " years old!");14、以下程序的输出结果为_ 课程号:101 课程名:JSP 学分:3 _。public class Course private String cNumber;private String cName;private int cUnit;public Course(String number, String name, int unit) cNumber = number;cName = name;cUnit = unit;public void printCourseInfo() System.out.println("课程号:" + cNumber + "课程名:" + cName + " 学分:" + cUnit);class CourseTest public static void main(String args) Course c;c = new Course("101", "JSP", 3);c.printCourseInfo();15、以下程序的输出结果为_ 汤姆猫体重：20.0斤 _。public class Tom private float weight;private static String name;public void setWeight(float weight) this.weight = weight;private void out() System.out.println(name + "体重：" + weight + "斤");public static void main(String args) Tom.name = "汤姆猫"Tom cat = new Tom();cat.setWeight(20);cat.out();16、以下程序的输出结果是 _姓名:Tom 年龄:15 家庭住址:宿城区 电话:66123456 学校：宿中_。public class Father String name, address, tel;int age;public Father(String name, int age) this.name = name;this.age = age;void out() System.out.print("姓名:" + name);System.out.print(" 年龄:" + age);void outOther() System.out.print(" 家庭住址:" + address);System.out.print(" 电话:" + tel);class Son extends Father String school;public Son(String name, int age) super(name, age);void out() super.out();super.outOther();System.out.println(" 学校：" + school);public static void main(String args) Son son = new Son("Tom", 15);son.address = "宿城区"son.school = "宿中"son.tel = "66123456"son.out();17、下列程序的运行结果是_ 12345_。public class MyClass int a = 1, 2, 3, 4, 5 ;void out() for (int j = 0; j < a.length; j+)System.out.print(aj + "");public static void main(String args) MyClass my = new MyClass();my.out();18、阅读下面的程序，回答问题。import java.awt.*; import javax.swing.*; public class T extends JFrame public T ( ) super("GridLayout"); Container con=this.getContentPane(); con.setLayout(new GridLayout(2,3); con.add(new JButton("a"); con.add(new JButton("b"); con.add(new JButton("c"); con.add(new JButton("d"); con.add(new JButton("e"); con.add(new JButton("f"); setSize(200, 80); setVisible(true); public static void main(String args) new T(); 画图表示程序运行后的图形界面。如果程序通过实现某个接口处理按钮的动作事件，则该接口名为何？接口中的方法头声明如何？答案：接口名：ActionListener 接口中的方法：public void actionPerformed(ActionEvent e)19、阅读下面的程序，并回答问题。import java.io.*;public class Test public static void main(String args) throws IOException BufferedReader buf=new BufferedReader( new InputStreamReader(System.in); while (true) String str = buf.readLine( ); if( str.equals("quit") ) break; int x = Integer.parseInt(str); System.out.println(x*x); 编译运行上面的程序：从键盘输入5，回车后输出的结果如何？从键盘输入quit，回车后程序执行情况如何？答案：25 终止应用程序的运行。20、阅读下面的程序代码，并回答问题。String s1 = new String("abcde");String s2 = new String("abcde"); boolean b1= s1.equals(s2);boolean b2 = s1= s2; System.out.print(b1+" "+b2); 程序段执行后，在命令行的输出结果如何？解释输出(1)的结果的原因？答案： true falseequals方法比较两个字符串的内容是否相等；运算符“=”判断两个对象是否指向同一个引用，即是否为同一个对象。21、阅读下面的程序，并回答问题。import java.io.*;public class Test public static void main(String args) throws IOException BufferedReader buf=new BufferedReader( new InputStreamReader(System.in); while (true) String str = buf.readLine(); if( str.equals("quit") ) break; int x = Integer.parseInt(str); System.out.println(x*x); 编译运行上面的程序：从键盘输入10，回车后输出的结果如何？从键盘输入exit，回车后程序能正确执行吗？为什么？答案：100 不能；因为方法Integer.parseInt(str)不能将字符串“exit”转化为整数，抛出异常。22、写出下面的程序编译、运行后的结果。public class Test public static void main(String args) new Student("Tom", 'm', 90, 88); new Student("Jack", 'm', 66, 89); new Student("Mary", 'f', 76, 86); System.out.println("nametsextchinesetenglish"); Student.print(); class Student protected String name; protected char sex; protected int chinese; protected int english; protected Student next; static Student list; Student (String name, char sex, int chinese, int english) this.name=name; this.sex=sex; this.chinese=chinese; this.english=english; this.next=list; list=this; static void print() Student friend=list; if (friend=null) System.out.println("The list is empty."); else do System.out.println(friend.toString(); friend=friend.next; while(friend!=null); public String toString() return new String(name+"t"+sex+"t"+chinese+"t"+english); 答案：name sex chinese englishMary f 76 86Jack m 66 89Tom m 90 8823、阅读下列程序：public class Sumpublic static void main(String args)int j=10;System.out.println("j is : "+j);calculate(j);System.out.println("At last, j is : "+j);static void calculate (int j)for (int i = 0;i<10;i+)j+;System.out.println("j in calculate() is: "+j);输出结果为：j is :  (1) j in calculate() is : (2)At last j is :  (3)答案：(1) 10； (2) 20； (3) 10。24、按要求填空abstract class SuperAbstractvoid a()abstract void b();abstract int c(int i);interface AsSuper void x( );abstract class SubAbstract extends SuperAbstract implements AsSuper public void b( )abstract String f( );public class InheritAbstract extends SubAbstractpublic void x( ) public int c(int i ) public String f( ) public static void main(String args)InheritAbstract instance = new InheritAbstract( );instance.x();instance.a();instance.b();instance.c(100);System.out.println(instance.f(); 在以上这段程序中：抽象类有：SuperAbstract和（1）(写出类名)非抽象类有：（2）(写出类名)接口有：（3）(写出接口名)AsSuper中的x()方法是（4）方法，所以在InheritAbstract中必须对它进行（5）答案：(1) SuperAbstract；(2) InheritAbstract；(3) AsSuper；(4) 抽象；(5) 覆盖和实现。25、按注释完成程序public class Leaf private int i = 0; /此属性值用于检验Leaf increment( ) /定义方法increment()，返回值是Leaf类的对象i+;return (1) _ ; /将当前对象的地址作为返回值返回void print( ) System.out.println(" i = " + i);public static void main(String args )Leaf x = (2) _ ; /创建Leaf类的对象xx.increment( ).increment( ).increment().print();/多次调用方法increment( )，返回的都是x的地址，i 值表示调用次数输出结果为 i = (3) _ 答案：(1) this；(2) new Leaf()；(3) 326、 按注释提示完成文件复制的程序 /FileStream源代码如下： import java.io.*; class FileStream public static void main(String args ) try File inFile = new File("file1.txt"); /指定源文件 File outFile = new File("file2.txt"); /指定目标文件 FileInputStream fis =（1）_ _; FileOutputStream fos = new FileOutputStream(outFile); int c; /逐字节从源文件中输入，再输出到fos流while (c = fis.read ()!=-1) （2）_; fis.close(); fos.close();catch (Exception e) System.out.println("FileStreamsTest: "+e); 答案：(1) new FileInputStream(inFile);(2) fos.write(c);27、阅读程序，写出结果：/ AbstractClassDemo.java源代码如下：abstract class Shape /定义抽象类Shape和抽象方法displayabstract void display();class Circle extends Shape void display() /实现抽象类的方法System.out.println("Circle");class Rectangle extends Shape void display() /实现抽象类的方法System.out.println("Rectangle");class Triangle extends Shape void display() /实现抽象类的方法System.out.println("Triangle");public class AbstractClassDemopublic static void main(String args)(new Circle().display();/定义无名对象来调用对应的display方法(new Rectangle().display();(new Triangle().display();输出结果是?答案：(1) Circle； (2) Rectangle； (3) Triangle。28、阅读下列代码，说出这段程序的功能。 import java.io.*; public class Test public static void main( String argv) try BufferedReader is = new BufferedReader( new InputStreamReader(System.in); String inputLine; While (inputLine = is.readLine ()!= null) System.out.println(inputLine); is.close(); catch (IOException e) System.out.println("IOException: " + e); 程序的功能是：_答案：读取键盘输入，显示到屏幕上，直到键盘输入为空为止。29、阅读下列程序，写出正确的运行结果。 class test public static void main (String args ) int x = 9, y; if ( x >= 0) if (x > 0)y = 1; else y = 0; else y = -1; System.out.println(y); 程序的输出结果是：_答案：130、 阅读程序，写出正确的运行结果。 public class Father int a = 100; public void miner( ) a-; public static void main(String args