java高级特征与实战项目

           第一章课后作业

4.创建一个类Queue 代表队列,添加add(Object o)及get()方法,并添加main方法进行验证

public class Queue {
LinkedList<Object> list = new LinkedList<Object>();
public void add(Object o) {
list.addFirst(o);
}
public Object get() {
if(!list.isEmpty()) {
return list.removeLast();
}
return "队列为空";
}
public static void main(String[] args) {
Queue q = new Queue();
q.add(1);
q.add(2);
System.out.print(q.get());
}

}

5.创建一个HashMap泛型对象，添加学员姓名分数，键为学员姓名值为学员对象，从HashMap中用迭代器打印学员成绩。 

import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
public class Test {
public static void main(String args[]) {
Map<String, Student> students = new HashMap<String, Student>();
students.put("aaa", new Student(60));
students.put("bbb", new Student(70));
students.put("ccc", new Student(80));
for (Entry<String, Student> entry : students.entrySet()) {
System.out.println("姓名:" + entry.getKey() + " 成绩:" + entry.getValue());
}
}
}
class Student {
public Student(int point) {
this.point = point;
}
private int point;
public int getPoint() {
return point;
}
public void setPoint(int point) {
this.point = point;
}
@Override
public String toString() {
return String.valueOf(this.point);
}
}