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Question

一：设计一个类Animal，含有私有的weight成员，写一个setweight函数修改这个成员，要求当传入非正值时，能主动抛出一个异常，并将weight设置为0
二：在Animal的基础上，派生出Dog类，并使用数组存储101个Dog对象，每只Dog的weight用[-100,100)之间的随机数赋值，设计最后成功设置了多少只Dog的weight
刚学java ，菜鸟一枚~·
大侠帮帮忙，感激不尽~~

Answer 1

代码如下，如有不明白的地方可以Hi我，我已经测试好了的～！
import java.util.ArrayList;
import java.util.List;
import java.util.Random;

class DataException extends Exception{}
class Animal {
private int weight;
public static int count = 0;//记录成功设置的数量
public void setWeight(int weight){
this.weight = weight;
if(this.weight<0){
try {
throw new DataException();
} catch (DataException e) {
// TODO Auto-generated catch block
System.out.println("weight:"+weight+" 必须为正值");
this.weight = 0;
}
}else{
count++;
}
}
}

class Dog extends Animal{}

public class DogTest {
public static void main(String[] args) {
// TODO Auto-generated method stub
List<Dog> dogs = new ArrayList<Dog>();
Random rand = new Random(47);
for(int i = 0;i<101;i++){
Dog dog = new Dog();
dog.setWeight(rand.nextInt(200)-100);
dogs.add(dog);
}
System.out.println("成功设置的Dog数："+Animal.count);
}

}

Answer 2

public class Animal{
private int weight;
public void setWeight(int weight) throws Exception{
if(weight<0){
weight =0;
throw new Exception();
}
}
public int getWeight(){
return weight;
}
public static void main(String[] args) {
Dog dog = new Dog();
dog.getDog();
}
}
class Dog extends Animal{
private Dog [] dogs;
public Dog [] getDog(){
dogs = new Dog[101];
int i=0;
for(i=0;i<101;i++){
int weight = (int) (Math.random()*-200+100);
Dog dog = new Dog();
try {
dog.setWeight(weight);
} catch (Exception e) {
System.out.println("成功设置了"+(i+1)+"只Dog");
return dogs;
}

dogs[i] = dog;
}
return dogs;
}
}

Answer 3

public class Animal{
private int weight;
public void setWeight(int weight){
if(weight<0){
this.weight=0;
}else{
this.weight=weight;
}
}
public int getWeight(){
return this.weight;
}
}

Answer 4

2楼写的不错，就不写了。