class Guy{String greet(){return “hi“}} class Cowboy extends Guy {String greet(){return“howdy”}} class Surfer extends Guy {String greet(){return“dudel”}} class Greetings{ public static void main (string[]args){ Guy[] guy= {new Guy(),new Cowboy(),new Surfer()}; for(Guy 0: guys) System.out.print(g.green()); } } 结果为:
第1题:
已知类 String 的原型为
class string
{
public:
string(const char *str=null);//普通构造函数
string(const string &other);//拷贝构造函数
---string(void);
string &operate=(const string &other);//赋值函数
private:
char * m-data;//用于保存字符串
};
请编写 string 的上述4 个函数
第2题:
Which statements concerning the following code are true?() class a { public a() {} public a(int i) { this(); } } class b extends a { public boolean b(String msg) { return false; } } class c extends b { private c() { super(); } public c(String msg) { this(); } public c(int i) {} }
第3题:
class Mineral { static String shiny() { return "1"; } } class Granite extends Mineral { public static void main(String [] args) { String s = shiny() + getShiny(); s = s + super.shiny(); System.out.println(s); } static String getShiny() { return shiny(); } } 结果为:()
第4题:
现有: class Guy {String greet() {return "hi"; } } class Cowboy extends Guy ( String greet() ( return "howdy ¨; ) ) class Surfer extends Guy (String greet() (return "dude! ";)) class Greetings { public static void main (String [] args) { Guy [] guys = ( new Guy(), new Cowboy(), new Surfer() ); for (Guy g: guys) System.out.print (g.greet()}; } } 结果为:()
第5题:
我们定义一个Account类来描述银行账户,银行账户有账户名、金额等属性特征,同时有存款、取款等行为特征,下述代码适合描述的是哪项?()
第6题:
You work as the application developer at Hi-Tech.com. You create a new custom dictionary named MyDictionary. Choose the code segment which will ensure that MyDictionary is type safe?()
第7题:
smith
null
SALES
编译错误
第8题:
Class MyDictionary Implements Dictionary (Of String,String)
Class MyDictionary Inherits HashTable
Class MyDictionary Implements IDictionary
Class MyDictionary End Class Dim t as New Dictionary (Of String, String) Dim dict As MyDIctionary= CType (t,MyDictionary)
第9题:
smith
null
编译错误
name
第10题:
The code will compile without changes.
The code will compile if public Tree() { Plant(); } is added to the Tree class.
The code will compile if public Plant() { Tree(); } is added to the Plant class.
The code will compile if public Plant() { this(”fern”); } is added to the Plant class.
The code will compile if public Plant() { Plant(”fern”); } is added to the Plant class.
第11题:
Person(n,a);
this(Person(n,a));
this(n,a);
this(name,age);
第12题:
hi hi ouch!
hi howdy ouch!
ouch! howdy ouch!
编译失败
第13题:
类Account中字段声明正确的是?()
第14题:
Which two allow the class Thing to be instantiated using new Thing()?
第15题:
public class Employee{ private String name; public Employee(String name){ this.name = name; } public String getName(){ return name; } } public class Manager extends Employee{ public Manager(String name){ System.out.println(getName()); } } 执行语句new Manager(“smith”)后程序的输出是哪项?()
第16题:
Which methods from the String and StringBuffer classes modify the object on which they are called?()
第17题:
public class Plant { private String name; public Plant(String name) { this.name = name; } public String getName() { return name; } } public class Tree extends Plant { public void growFruit() { } public void dropLeaves() { } } Which is true?()
第18题:
public void main(String args[])
public void static main(String args[])
public static main(String[] argv)
final public static void main(String [] array)
public static void main(String args[])
第19题:
运行时异常被输出
第7行出现一个错误,编译失败
第8行出现一个错误,编译失败
hi hi hi
hi hawdy doude
第20题:
The charAt() method of the String class.
The toUpperCase() method of the String class.
The replace() method of the String class.
The reverse() method of the StringBuffer class.
The length() method of the StringBuffer class.
第21题:
public class Thing { }
public class Thing { public Thing() {} }
public class Thing { public Thing(void) {} }
public class Thing { public Thing(String s) {} }
public class Thing { public void Thing() {} public Thing(String s) {} }
第22题:
hi hi ouch!
ouch! howdy ouch!
hi howdy ouch!
编译失败
运行的咐候有异常抛出
第23题:
hi howdy dude!
运行时异常被抛出。
第7行出现一个错误,编译失败。
第8行出现一个错误,编译失败。
第24题:
insert a call to this() in the Car constructor
insert a call to this() in the MeGo constructor
insert a call to super() in the MeGo constructor
insert a call to super(vin) in the MeGo constructor
change the wheelCount variable in Car to protected
change line 3 in the MeGo class to super.wheelCount = 3;