Java 面向对象案例 03（黑马）

代码：

public class phoneTest {public static void main(String[] args) {phone [] arr = new phone[3];phone p1 = new phone("华为",6999,"白色");phone p2 = new phone("vivo",4999,"蓝色");phone p3 = new phone("苹果",7999,"黑色");arr[0]=p1;arr[1]=p2;arr[2]=p3;double avg = (p1.getPrice()+ p2.getPrice()+p3.getPrice())/3;System.out.println(avg);}
}

public class phone {private String brand;private double price;private String color;public phone() {}public phone(String brand, double price, String color) {this.brand = brand;this.price = price;this.color = color;}public String getBrand() {return brand;}public void setBrand(String brand) {this.brand = brand;}public double getPrice() {return price;}public void setPrice(double price) {this.price = price;}public String getColor() {return color;}public void setColor(String color) {this.color = color;}
}

运行结果：

代码：

public class girlTest {public static void main(String[] args) {girl [] arr = new girl[4];girl g1 = new girl("小红",18,'女',"跳舞");girl g2 = new girl("小芳",22,'女',"唱歌");girl g3 = new girl("小刘",23,'女',"骑车");girl g4 = new girl("小美",19,'女',"爬山");arr[0]=g1;arr[1]=g2;arr[2]=g3;arr[3]=g4;double sum=0;for(int i=0;i<arr.length;i++){girl girl=arr[i];sum+=girl.getOld();}double avg = sum/arr.length;System.out.println(avg);int count=0;//统计思想for(int i=0;i<arr.length;i++){girl girl=arr[i];if(girl.getOld()<avg) {count++;System.out.println(girl.getName() + "," + girl.getOld() + "," + girl.getHobby() + "," + girl.getSex());}}System.out.println("有"+count+"个");}
}

public class girl {private String name;private int old;private char sex;private String hobby;public girl() {}public girl(String name, int old, char sex, String hobby) {this.name = name;this.old = old;this.sex = sex;this.hobby = hobby;}public String getName() {return name;}public void setName(String name) {this.name = name;}public int getOld() {return old;}public void setOld(int old) {this.old = old;}public char getSex() {return sex;}public void setSex(char sex) {this.sex = sex;}public String getHobby() {return hobby;}public void setHobby(String hobby) {this.hobby = hobby;}
}

代码结果：

自己写的代码：

import java.sql.SQLOutput;
import java.util.Scanner;
public class studentTest {public static void main(String[] args) {Scanner input = new Scanner (System.in);student [] arr = new student[3];student s1 = new student("heima001","小白",19);student s2 = new student("heima002","小黑",19);student s3 = new student();arr[0]=s1;arr[1]=s2;arr[2]=s3;System.out.println("输入第3个同学的学号：");boolean flag = true;do {String n = input.next();if ((!n.equals(s1.getNov())) && (!n.equals(s2.getNov()))) {s3.setNov(n);flag=false;} else {System.out.println("该用户已存在，输入失败,请重新输入：");}}while(flag);System.out.println("输入第3个同学的名字：");String m = input.next();s3.setName(m);System.out.println("输入第3个同学的年龄：");int q = input.nextInt();s3.setAge(q);for(int i=0;i<arr.length;i++){student student = arr[i];System.out.println(student.getNov()+","+student.getName()+","+student.getAge());}System.out.println("请输入要删除的学生的学号：");String p = input.next();int count =0;for(int j=0;j< arr.length;j++){student student = arr[j];if(p.equals(student.getNov())) {student.setAge(0);student.setName(null);student.setNov(null);System.out.println("删除成功");break;}else{count++;}if(count==arr.length){System.out.println("删除失败");}}for(int i=0;i<arr.length;i++){student student = arr[i];System.out.println(student.getNov()+","+student.getName()+","+student.getAge());}for(int i=0;i<arr.length;i++){student student = arr[i];if(student.getNov()=="heima002"){int age =student.getAge()+1;student.setAge(age);System.out.println(student.getAge());}//System.out.println(student.getNov()+","+student.getName()+","+student.getAge());}}
}

public class student {private String Nov;private String name;private int age;public student() {}public student(String nov, String name, int age) {Nov = nov;this.name = name;this.age = age;}public String getNov() {return Nov;}public void setNov(String nov) {Nov = nov;}public String getName() {return name;}public void setName(String name) {this.name = name;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}
}

缺少如果数组满了要添加对象进去的判断：

1、判断id是否重复：