Java学习笔记6
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题目1
import java.util.Random;
public class role {
private String name;
private int blood;
//有参构造
public role() {
}
//有参构造
public role(String name, int blood) {
this.name = name;
this.blood = blood;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getBlood() {
return blood;
}
public void setBlood(int blood) {
this.blood = blood;
}
//定义一个方法用于攻击别人
//role n1 = new role();
//role n2 = new role();
//n1.攻击(n2);
//方法的调用者去攻击参数
public void attack(role role){
Random r = new Random();
//造成伤害1-20点血
int hurt = r.nextInt(20)+1;
//剩余血量
int remainBlood = getBlood()-hurt;
//判断血量是否为负
remainBlood = remainBlood < 0 ? 0:remainBlood;
//修改一下挨揍人的血量
role.setBlood(remainBlood);
//This代表方法的调用者
System.out.println(this.getName() + "挥起拳头打了"+role.getName()+"一下，造成了"+hurt+"伤害，"+role.getName()+"还剩下"+role.getBlood()+"点血");
}
}
测试
public class roleTest {
public static void main(String[] args) {
//创建对象
role n1 = new role("乔峰",100);
role n2 = new role("鸠摩智",100);
//开始格斗，回合制游戏
while(true){
n1.attack(n2);
if(n2.getBlood()==0){
System.out.println(n1.getName()+"K.O"+n2.getName());
break;
}
n2.attack(n1);
if(n1.getBlood()==0){
System.out.println(n2.getName()+"K.O"+n1.getName());
break;
}
}
}
}
题目二
public class role {
private String id;
private String name;
private double price;
private int count;
public role() {
}
public role(String id, String name, double price, int count) {
this.id = id;
this.name = name;
this.price = price;
this.count = count;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public double getPrice() {
return price;
}
public void setPrice(double price) {
this.price = price;
}
public int getCount() {
return count;
}
public void setCount(int count) {
this.count = count;
}
}
测试
public class roleTest {
public static void main(String[] args) {
role[]arr = new role [3];
role g1 = new role("001","华为",90,10);
role g2 = new role("002","苹果14",8999,100);
role g3 = new role("003","三星",8000,100);
arr[0] = g1;
arr[1] = g2;
arr[2] = g3;
for (int i = 0; i < arr.length; i++) {
role goods = arr[i];
System.out.println(goods.getId() +","+ goods.getName()+","+goods.getPrice()+","+goods.getCount());
}
}
}
键盘录入
第一套体系
nextInt();接收整数
nextInt();接收小数
next();接收字符串
遇到空格，制表符，回车就停止接收。这些符号后面的数据就不会接受了。
第二套体系
nextLine();接收字符串
可以接收空格，制表符，遇到回车才停止接收数据
自动生成左边，Ctrl+Alt+V
题目三
定义数组存储3部汽车对象
汽车的属性：品牌，价格，颜色
创建三个汽车对象，数据通过键盘录入而来，并把数据存入到数组当中
public class Car {
//对象属性
private String brand;
private int price;
private String color;
//空参，全参
public Car() {
}
public Car(String brand, int 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 int getPrice() {
return price;
}
public void setPrice(int price) {
this.price = price;
}
public String getColor() {
return color;
}
public void setColor(String color) {
this.color = color;
}
}
测试
import java.util.Scanner;
public class CatText {
public static void main(String[] args) {
//创建一个数组
Car[]arr = new Car[3];
//键盘录入
Scanner sc = new Scanner(System.in);
for (int i = 0; i < arr.length; i++) {
//创建汽车对象
Car c = new Car();
//录入汽车品牌·
System.out.println("请输入汽车品牌：");
String brand = sc.next();
c.setBrand(brand);
//录入汽车价格
System.out.println("请输入汽车的价格：");
int price = sc.nextInt();
c.setPrice(price);
//录入汽车颜色
System.out.println("请输入汽车颜色：");
String color = sc.next();
c.setColor(color);
//把汽车对象添加到数组当中
arr[i] = c;
}
for (int i = 0; i < arr.length; i++) {
Car cars = arr[i];
System.out.println(cars.getBrand()+","+cars.getPrice()+","+cars.getColor());
}
}
}
题目四
public class Student {
private int id;
private String name;
private int age;
public Student() {
}
public Student(int id, String name, int age) {
this.id = id;
this.name = name;
this.age = age;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
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;
}
}
第1，2问测试
public class StudentText {
public static void main(String[] args) {
//创建一个数组
Student[] arr = new Student[3];
//创建学生对象
Student st1 = new Student(01, "张三", 23);
Student st2 = new Student(02, "李四", 24);
Student st3 = new Student(03, "王五", 25);
//把学生对象弄到数组当中
arr[0] = st1;
arr[1] = st2;
arr[2] = st3;
//再次添加一个学生对象，并再添加的时候进行学号唯一性判断
Student st4 = new Student(04, "赵六", 26);
//判断唯一性
boolean flag = contains(arr, st4.getId());
if (flag) {
System.out.println("当前id已重复，请重新输入");
} else {
//数组如果已满，新建数组,长度是老数组+1
int count = getcount(arr);
if (count == arr.length) {
Student[] newArr = creatNewArr(arr);
newArr[count] = st4;
printArr(newArr);
}else{
arr[count] = st4;
printArr(arr);
}
}
}
//方法判断唯一性
public static boolean contains(Student[]arr,int id){
for (int i = 0; i < arr.length; i++) {
//依次获取数组中每一个学生对象
Student st = arr[i];
//判断数组是否为空
if(st != null){
//获取数组中学生对象的id
int sid = st.getId();
if(sid == id){
return true;
}
}
}
return false;
}
//方法判断数组里存了几个元素
public static int getcount(Student[]arr){
//定义一个计数器
int count = 0;
for (int i = 0; i < arr.length; i++) {
if(arr[i] != null){
count++;
}
}
return count;
}
//数组已满，创建新数组
public static Student [] creatNewArr(Student[]arr){
Student []newArr = new Student[arr.length+1];
for (int i = 0; i < arr.length; i++) {
newArr[i] = arr[i];
}
return newArr;
}
//两个地方打印
public static void printArr(Student[]arr){
for (int i = 0; i < arr.length; i++) {
Student stu = arr[i];
if(stu != null){
System.out.println(stu.getId()+", "+stu.getName()+", "+ stu.getAge());
}
}
}
}
第3.4两问
public class Student {
private int id;
private String name;
private int age;
public Student() {
}
public Student(int id, String name, int age) {
this.id = id;
this.name = name;
this.age = age;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
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;
}
}
测试
public class StudentText {
public static void main(String[] args) {
//创建一个数组
Student[] arr = new Student[3];
//创建学生对象
Student st1 = new Student(01, "张三", 23);
Student st2 = new Student(02, "李四", 24);
Student st3 = new Student(03, "王五", 25);
//把学生对象弄到数组当中
arr[0] = st1;
arr[1] = st2;
arr[2] = st3;
//通过学生id删除学生信息，如果id存在则删除，如果id不存在，则提示删除失败
int index = getIndex(arr, 1);
//找到id在数组中的索引
if(index >= 0){
arr[index] = null;
printArr(arr);
}else{
System.out.println("当前id不存在，删除失败");
}
}
//找到id在数组当中的索引
public static int getIndex(Student[]arr,int id){
for (int i = 0; i < arr.length; i++) {
Student stu = arr[i];
if(stu != null){
int sid = stu.getId();
if(sid == id){
return i;
}
}
}
//当循环结束之后，还没有找到就表示不存在
return -1;
}
public static void printArr(Student[]arr){
for (int i = 0; i < arr.length; i++) {
Student stu1 = arr[i];
if(stu1 != null){
System.out.println(stu1.getId()+", "+ stu1.getAge()+", "+stu1.getName());
}
}
}
}
第五小5问
public class StudentText {
public static void main(String[] args) {
//创建一个数组
Student[] arr = new Student[3];
//创建学生对象
Student st1 = new Student(01, "张三", 23);
Student st2 = new Student(02, "李四", 24);
Student st3 = new Student(03, "王五", 25);
//把学生对象弄到数组当中
arr[0] = st1;
arr[1] = st2;
arr[2] = st3;
//通过学生id删除学生信息，如果id存在则删除，如果id不存在，则提示删除失败
int index = getIndex(arr, 1);
//找到id在数组中的索引
if(index >= 0){
arr[index] = null;
printArr(arr);
}else{
System.out.println("当前id不存在，删除失败");
}
}
//找到id在数组当中的索引
public static int getIndex(Student[]arr,int id){
for (int i = 0; i < arr.length; i++) {
Student stu = arr[i];
if(stu != null){
int sid = stu.getId();
if(sid == id){
return i;
}
}
}
//当循环结束之后，还没有找到就表示不存在
return -1;
}
public static void printArr(Student[]arr){
for (int i = 0; i < arr.length; i++) {
Student stu1 = arr[i];
if(stu1 != null){
System.out.println(stu1.getId()+", "+ stu1.getAge()+", "+stu1.getName());
}
}
}
}
测试
public class StudentText {
public static void main(String[] args) {
//创建一个数组
Student[] arr = new Student[3];
//创建学生对象
Student st1 = new Student(01, "张三", 23);
Student st2 = new Student(02, "李四", 24);
Student st3 = new Student(03, "王五", 25);
//把学生对象弄到数组当中
arr[0] = st1;
arr[1] = st2;
arr[2] = st3;
//先找到id为2的索引
int index = getIndex(arr, 2);
//判断是否存在
if(index >= 0){
//存在
Student stu = arr[index];
//拿出年龄+1
int newAge = stu.getAge() + 1;
//把+1的年龄放回去
stu.setAge(newAge);
//遍历
printArr(arr);
}
}
//找到id在数组当中的索引
public static int getIndex(Student[]arr,int id){
for (int i = 0; i < arr.length; i++) {
Student stu = arr[i];
if(stu != null){
int sid = stu.getId();
if(sid == id){
return i;
}
}
}
//当循环结束之后，还没有找到就表示不存在
return -1;
}
public static void printArr(Student[]arr){
for (int i = 0; i < arr.length; i++) {
Student stu1 = arr[i];
if(stu1 != null){
System.out.println(stu1.getId()+", "+ stu1.getAge()+", "+stu1.getName());
}
}
}
}
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