下列程序段的执行结果为（）。 a=3 b=1 ForI=1To3 f=a+b a=b b=f Printf NextI
A: extends和implements
B: public，private和protected
C: class和public
D: char，int，float和double
A: extends和implements
B: public，private和protected
C: class和public
D: char，int，float和double
举一反三
- 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】 } }
- 已知： class A { public: int a; int b(); int f(); int f(int); int g(); }; class B { public: char f(); int g(); private: int a; int b(); }; class C:public A,public B { }; 设有：C *pc; 则：
- 程序填空：interface Com{ int M=200; int f(); } class ImpCom implements Com{ ___________________________; } A: public int f(){retrun 100+M;} B: int f() {return 100;} C: public double f(){return 2.6;} D: public abstract inf f();
- 假设C和D是接口，下列定义哪个是正确的（） A: public class A implements C,D｛ ｝ B: public class A implements C implements D｛ ｝ C: public class A extends C,D｛ ｝ D: public class A extends C extends D｛ ｝
- 以下代码输出结果为()class A{ public $a = 1; protected $b = 2;}class B extends A{ public $b = 3; function __construct(){ echo $this->a+$this->b; }}$b = new B(); A: 1 B: 2 C: 3 D: 4