interfaceA{doublef(doublex,doubley);}classBimplementsA{publicdoublef(doublex,doubley){returnx*y;}intg(inta,intb){returna+b;}}publicclassE{publicstaticvoidmain(Stringargs[]){Aa=newB();System.out.println(a.f(3,5));//【代码1】Bb=(B)a;System.out.println(b.g(3,5));//【代码2】}}代码1输出()代码2输出()
举一反三
- 下列程序段运行结果是()interfaceA{doublef(doublex,doubley);}classBimplementsA{publicdoublef(doublex,doubley){returnx*y;}intg(inta,intb){returna+b;}}publicclassE{publicstaticvoidmain(String[]args){Aa=newB();System.out.println(a.f(3,5));Bb=(B)a;System.out.println(b.g(3,5));}} A: 15.0,8.0 B: 15.08 C: 158 D: 815
- 下列程序标注的【代码1】，【代码2】的输出结果是什么？ publicclassE{ publicstaticvoidmain(Stringargs[]){ int[]a={10,20,30,40},b[]={{1,2},{4,5,6,7}}; b[0]=a; b[0][1]=b[1][3]; System.out.println(b[0][3]);//【代码1】 System.out.println(a[1]);//【代码2】 } }
- 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】 } }
- 中国大学MOOC:编译并运行下面的程序，运行结果为（ ）。publicclassMain{publicstaticvoidmain(String[]args){AAobj=newBB();System.out.println(obj.f(4,6));}}classAA{doublef(doublex,doubley){returnx*y;}}classBBextendsAA{doublef(doublex,doubley){returnx+y;}}
- 阅读下列代码 PublicclassTest { Publicstaticvoidmain(Stringargs[]) { System.out.println((3>2)?4:5); } } 其运行结果是()