• 2022-05-28
    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) ;}}
  • 100

    举一反三

    内容

    • 0

      请说出E类中【代码1】,【代码2】的输出结果。 interface A { double f(double x,double y); } class B implements A { public double f(double x,double y) { return x*y; } int g(int a,int b) { return a+b; } } public class E { public static void main(String args[]) { A a = new B(); System.out.println(a.f(3,5)); //【代码1】 B b = (B)a; System.out.println(b.g(3,5)); //【代码2】 } }

    • 1

      class Demo{ public static void main(String[] args){ int x = 0; try{ x = div(1,2); }catch(Exception e){ System.out.println(e); } System.out.println(x) ; } public static int div(int a,int b){ return a / b ; } }

    • 2

      class A { public int f(int x,int y) { return x+y; } } class B extends A { public int f(byte x,int y) { return x*y; } } 子类B的对象只能调用子类中的f方法。( )

    • 3

      下列代码的输出结果是( )interface Com{ int M=100; int on();}class A implements Com{ public int on(){ return Com.M; }}public class E{ public static void main(String args[]){ Com com=new A(); int m=com.on(); System.out.println(m); }}

    • 4

      以下程序运行结果是 public class Test { public static void main(String[] args) { int a=1,b[]={2}; add(a); add(b); System.out.println(a+","+b[0]); } static int add(int x){ x++; return x; } static void add(int[] x){ x[0]++; } }