• 2021-04-14
    class Person {private int a;public int change(int m){ return m; }}public class Teacher extends Person {public int b;public static void main(String arg[]){Person p = new Person();Teacher t = new Teacher();int i;// point x}}在 // point x安排哪个语句合法?
  • i = p.change(30);

    举一反三

    内容

    • 0

      请写出下列程序的输出结果。class A{public int f(int x) {return x+1;}}class B extends A{public int f(int x){return x*x;}}public class E{public static void main(String args[]){A a=new B();int m=a.f(10);System. out. println(m) ;}}

    • 1

      在C#中,下列结构或者类定义正确的是(选一项) A: public struct Person{ string name; int age; public void ShowName(){ Console.WriteLine(name); }} B: public struct Person{ string name; int age; public Person(){ Conssole.WriteLine(name); }} C: public class Person{ string name; int age; public Person(){ Conssole.WriteLine(name); }} D: public class Person{ string name; int age; public Person(string name){ Conssole.WriteLine(name); }}

    • 2

      (7-1)请阅读程序,并写出程序运行结果。 class X{ int getX() { return 5; } } class Y extends X{ int getX() { return 6; } } class T extends X{ int getX() { return 7; } } public class Demo10 { public static void main(String[] args) { X x=new X(); Y y=new Y(); X t=new T(); int sum=x.getX()+y.getX()+t.getX(); System.out.println(sum); } }

    • 3

      根据下面给出的代码,判断那个叙述是对的?public class Person{static int arr[]=new int[10];public static void main(String a[]){System.out.println(arr[1]);}}

    • 4

      阅读下面的程序,输出结果是()public class TestDemo{int m=5;public void some(int x){m=x;}public static void main(String args[]) {new Demo().some(7);}}class Demo extends TestDemo{int m=8;public void some(int x) {super.some(x);System.out.println(m);}} A: 5 B: 8 C: 7 D: 编译错误