举一反三
- public class test1 { public static int add(int a, int b) { return a+b; } public static double add(double a, double b) { return a+b; } ________________ ___________________ { ________________ ___________________ } public static void main(String[] args) { System.out.println("调用add方法:"+add(2.1,3.4,4.5)); } }
- 以下代码运行后输出的内容（ ）public class Main { public static double div(int a, int b) { return (double)a/b; } public static int div(int a, int b) { return a/b; } public static void main(String[] args) { System.out.println(div(5, 2)); } } A: 2.5 B: 2 C: 输出内容不确定 D: 程序错误，无法运行
- 请阅读下面的程序 public class Demo { public static void sum(int a, int b) { System.out.println("int:" + (a + b)); } public static void sum(int a, float b) { System.out.println("float:" + (a + b)); } public static void sum(int a, double b) { System.out.println("double:" + (a + b)); } public static void main(String[] args) { int a = 10; long b = 20; sum(a, b); } } 下列选项中,哪一个是程序的运行结果()
- 关于下列代码说法正确的是( ) public class Foo{ public int add(int a,int b){ return a+b; } public static void main(String[] args){ Foo foo = null; System.out.println(foo.add(10,20)); } }
- 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】 } }
内容
- 0
程序如下： public (1) abc(int a,int b){ System.out.println(a+b); return (a+b); } 程序正确运行，（1）处应该填入（ ） A: void B: static C: int D: String
- 1
不能与该方法构成重载的方法是（） public double fun(int x，double y){ return x + y; } A: public void fun(int x){ System.out.println("x * x="+(x*x)); } B: public void fun(int a, double b){ System.out.println("a +b ="+(a+b)); } C: public int fun(int x, int y,int z){ renturn (x+y+z); } D: public double fun(double x, int y){ return x * y ; }
- 2
以下程序的运行结果是______ class A{public int getNumber(int a){return a+1;}}class B extends A{public int getNumber(int a, char c){return a+2;} public static void main(String[] args) {B b=new B();System.out.println(b.getNumber(0));} }
- 3
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 ; } }
- 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]++; } }