方法的内存

方法调用的基本内存原理

基本数据类型和引用数据类型

方法传递基本数据类型的内存原理

方法传递引用数据类型的内存原理

package com.itheima.loopdemo;
import java.util.Scanner;

public class test {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入机票的原价");
        int ticket = sc.nextInt();
        System.out.println("请输入当前的月份");
        int month = sc.nextInt();
        System.out.println("请输入当前购买的舱位 0 为头等舱 1 为经济舱");
        int seat = sc.nextInt();
        if (month>=5 &&month<=10){
            if (seat == 0) {
                ticket = (int) (ticket * 0.9);
            } else if (seat == 1) {
                ticket = (int)(ticket* 0.85);
            }
        } else if ((0<month && month<5) || (month>10 && month<=12)) {
            if (seat == 0) {
                ticket = (int) (ticket * 0.7);
            } else if (seat == 1) {
                ticket = (int)(ticket* 0.65);
            }
        }else{
            System.out.println("录入不合法");
        }
        System.out.print("最终票价为:" + ticket);
    }

加入方法

package com.itheima.loopdemo;
import java.util.Scanner;

public class test {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入机票的原价");
        int ticket = sc.nextInt();
        System.out.println("请输入当前的月份");
        int month = sc.nextInt();
        System.out.println("请输入当前购买的舱位 0 为头等舱 1 为经济舱");
        int seat = sc.nextInt();
        if (month>=5 &&month<=10){
            ticket = getPrice(ticket,seat,0.9,0.85);
        } else if ((0<month && month<5) || (month>10 && month<=12)) {
            ticket = getPrice(ticket,seat,0.7,0.65);
        }else{
            System.out.println("录入不合法");
        }
        System.out.print("最终票价为:" + ticket);
    }
    //我要干嘛?跟陆
    public static int getPrice(int ticket,int seat,double v0,double v1){
        if (seat == 0){
            ticket = (int)(ticket * v0);
        } else if (seat == 1) {
            ticket = (int)(ticket * v1);
        }else {
            System.out.println("没有这个舱位");
        }
        return ticket;
    }
}

快捷键小知识

Ctrl + Alt + L 快速整理代码

Ctrl + Alt + M 快速生成方法

package com.itheima.loopdemo;
import java.util.Scanner;
import java.util.Random;

public class test {
    public static void main(String[] args) {
        // 1. 生成中奖号码
        int[] arr = createNumber();

        // 2. 用户输入号码
        int[] userInputArr = userInputNumber();

        // 3. 统计红球和蓝球中奖个数
        int redCount = 0;
        int blueCount = 0;

        // 注意：只比对前6位红球
        for (int i = 0; i < 6; i++) {
            int userRed = userInputArr[i];
            for (int j = 0; j < 6; j++) {
                if (userRed == arr[j]) {
                    redCount++;
                    break;
                }
            }
        }
        // 比对最后一位蓝球
        if (userInputArr[6] == arr[6]) {
            blueCount++;
        }

        // 4. 判定奖项
        System.out.println("中奖号码为: ");
        printArray(arr);
        System.out.println("您的号码为: ");
        printArray(userInputArr);

        judge(redCount, blueCount);
    }

    // 生成中奖号码
    public static int[] createNumber() {
        int[] arr = new int[7];
        Random r = new Random();
        for (int i = 0; i < 6; ) { // 注意这里不写i++
            int redNumber = r.nextInt(33) + 1;
            if (!contains(arr, redNumber)) {
                arr[i] = redNumber;
                i++; // 只有成功放入才自增
            }
        }
        arr[6] = r.nextInt(16) + 1;
        return arr;
    }

    // 用户输入号码
    public static int[] userInputNumber() {
        int[] arr = new int[7];
        Scanner sc = new Scanner(System.in);

        // 输入红球
        for (int i = 0; i < 6; ) {
            System.out.println("请输入第" + (i + 1) + "个红球号码(1-33):");
            int num = sc.nextByte();
            if (num >= 1 && num <= 33) {
                if (!contains(arr, num)) {
                    arr[i] = num;
                    i++;
                } else {
                    System.out.println("号码已存在，请重新输入");
                }
            } else {
                System.out.println("超出范围，请输入1-33之间的数字");
            }
        }

        // 输入蓝球
        while (true) {
            System.out.println("请输入蓝球号码(1-16):");
            int blueNumber = sc.nextInt();
            if (blueNumber >= 1 && blueNumber <= 16) {
                arr[6] = blueNumber;
                break;
            } else {
                System.out.println("蓝球号码超出范围");
            }
        }
        return arr;
    }

    // 判断数组中是否包含某个数
    public static boolean contains(int[] arr, int number) {
        for (int i = 0; i < 6; i++) { // 只需检查红球部分
            if (arr[i] == number) return true;
        }
        return false;
    }

    // 打印数组
    public static void printArray(int[] arr) {
        for (int i = 0; i < arr.length; i++) {
            System.out.print(arr[i] + " ");
        }
        System.out.println();
    }

    // 判定奖项逻辑
    public static void judge(int redCount, int blueCount) {
        System.out.println("您中了 " + redCount + " 个红球, " + blueCount + " 个蓝球");
        if (redCount == 6 && blueCount == 1) {
            System.out.println("恭喜你,中奖1000万");
        } else if (redCount == 6 && blueCount == 0) {
            System.out.println("恭喜你,中奖500万");
        } else if (redCount == 5 && blueCount == 1) {
            System.out.println("恭喜你,中奖3000元");
        } else if ((redCount == 5 && blueCount == 0) || (redCount == 4 && blueCount == 1)) {
            System.out.println("恭喜你,中奖200元");
        } else if ((redCount == 4 && blueCount == 0) || (redCount == 3 && blueCount == 1)) {
            System.out.println("恭喜你,中奖10元");
        } else if (blueCount == 1) {
            System.out.println("恭喜你,中奖5元");
        } else {
            System.out.println("谢谢参与");
        }
    }
}

二维数组

二维数组的静态初始化