课后练习4: package one; public class Dog { private String name; private brain; public Dog(String name,String brain) { this.name = name; this.brain = brain; } public String getName() { return name; } public String getBrain() { return brain; } } package one; import java.util.LinkedList; import java.util.Set; public class Queue { public static void main(String[] args) { Dog piDog = new Dog("皮皮","拉布拉多"); Dog nuDog = new Dog("努努","雪纳瑞"); Dog miDog = new Dog("咪咪","拉布拉多"); Dog suDog = new Dog("苏苏","赖皮狗"); LinkedList<Dog> dogs = new LinkedList(); dogs.addFirst(piDog); dogs.addFirst(nuDog); dogs.addFirst(miDog); dogs.addFirst(suDog); for(Dog dog:dogs) { System.out.println(dog.getBrain()+" "+dog.getName()); }
dogs.removeLast();
for(Dog dog:dogs) { System.out.println(dog.getBrain()+" "+dog.getName()); }}}课后练习5:package one;public class Students {private String name;private int scores;public String getName() {return name;}public int getScores() {return scores;}public Students(String name,int scores) {this.name = name;this.scores = scores;}}package one;import java.util.HashMap;public class Hash {public static void main(String[] args) {Students duan = new Students("段海峰",65);Students ou = new Students("欧阳松涛",90);Students guo = new Students("郭振",75);HashMap<String,Students> students = new HashMap<String,Students>();students.put(duan.getName(), duan);students.put(ou.getName(), ou);students.put(guo.getName(), guo);for (String key : students.keySet()) {System.out.println("学员"+key+"的成绩为:"+students.get(key).getScores());}System.out.println();duan = new Students("段海峰",75);students.put(duan.getName(), duan);for (String key : students.keySet()) {System.out.println("学员"+key+"的成绩为:"+students.get(key).getScores());}}}