超星 - 网络211复习--填空 - 查题吧

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写出下列程序段的运行结果classA{doublef(doublex,doubley){returnx*y;}}classBextendsA{doublef(doublex,doubley){returnx+y;}}publicclassTest{publicstaticvoidmain(Stringargs[]){Bobj=newB();System.out.println("Theprogramoutputis"+obj.f(4,6));}}

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写出下列程序段的运行结果publicclassUnchecked{publicstaticvoidmain(String[]args){try{method();}catch(Exceptione){System.out.println("A");}finally{System.out.println("B");}}staticvoidmethod(){try{wrench();System.out.println("C");}catch(ArithmeticExceptione){System.out.println("D");}finally{System.out.println("E");}System.out.println("F");}staticvoidwrench(){thrownewNullPointerException();}}

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写出下列程序段的运行结果class father{void speak(){System.out.println("I am father!");}}public class son extends father{void speak(){super.speak();System.out.println("I am son!");}public static void main(String args[]){son cxz=new son();cxz.speak();}}

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/*** 往文件中依次写入3名员工的信息，* 每位员工有工龄和姓名两个字段然后按照* 第二名,第一名，第三名的先后顺序读取员工信息*/import java.io.File;import java.io.RandomAccessFile;public class RandomAccessFileTest {public static void main(String[] args) throws Exception {Employee employee1 = new Employee(5, "张三");Employee employee2 = new Employee(6, "lisi");Employee employee3 = new Employee(7, "James");File file = new File("employee.txt");if(!file.exists()){(1) //如果文件不存在，则新建文件}//设置文件的打开方式为读写RandomAccessFile randomAccessFile = new RandomAccessFile(file, "rw");randomAccessFile.writeChars(employee1.getName());//写出第一个员工的姓名randomAccessFile.writeInt(employee1.getWork_age());//写出第一个员工的工龄randomAccessFile.writeChars(employee2.getName());randomAccessFile.writeInt(employee2.getWork_age());randomAccessFile.writeChars(employee3.getName());randomAccessFile.writeInt(employee3.getWork_age());randomAccessFile.close();//关闭文件RandomAccessFile raf2 =(2)//以只读方式打开文件(3)//跳过第一个员工String strName2 = "";for(int i=0;i

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//打印1000之内的完数(一个数如果恰好等于除它本身外的因子之和，这个数就称为完数//例如6=1＋2＋3，6的因子是1,2,3)。public class Wanshu{public static void main (String args[ ]){int sum,i,j;for(i=1;i<=1000;i++){for(j=1,sum=0;j<=i/2;j++){(1) {sum=sum+j;}}if(2) {System.out.printf("%8d是一个完数%n",i);}}}}

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//线程A等待线程B的执行public class Dengdai{public static void main(String args[ ]){KThread a=new KThread ();a.threadA.start();}}class KThread implements Runnable{Thread threadA,threadB;String content[ ]={"今天晚上,","六点钟开始","在201实验室,","全班同学","上java实验！"};KThread(){(1)(2)threadB.setName("老师");}public void run(){if(Thread.currentThread()==threadA){System.out.println("我等"+threadB.getName()+"讲完我在提问！");threadB.start();while(threadB.isAlive()==false){}try{ (3) //线程threadA开始等待threadB结束}catch(InterruptedException e){}System.out.printf("\n老师:\"这个问题该怎么解决,谢谢老师\"");}else if(Thread.currentThread()==threadB){System.out.println(threadB.getName()+"说:");for(int i=0;i

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写出下列程序段的运行结果class Parent {String one, two;public Parent(String a, String b){one = a;two = b;}public void print(){ System.out.println(one); }}public class Child extends Parent {public Child(String a, String b){super(a,b);}public void print(){System.out.println(one + " to " + two);}public static void main(String args[]){Parent p = new Parent("south", "north");Parent t = new Child("east", "west");p.print();t.print();}}

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写出下列程序段的运行结果class change{void changeint(int x){x++;} public static void main(String args[]){int a=2;System.out.println("Before changed:"+"a="+a);change cxz=new change();cxz.changeint(a);System.out.println("After changed:"+"a="+a);}}

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写出下列程序段的运行结果abstract class Shape {abstract void display();}class Circle extends Shape {void display() {System.out.println("Circle");}}class Rectangle extends Shape {void display() {System.out.println("Rectangle");}}class Triangle extends Shape {void display() {System.out.println("Triangle");}}public class AbstractClassDemo{public static void main(String args[]){(new Circle()).display();(new Rectangle()).display();(new Triangle()).display();}}

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写出下列程序段的运行结果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 ( a[j]

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