一维数组java练习

1、打印下列图形
       *                 *
      ***               * *
     *****             * * *
    *******           * * * *
     *****             * * *
      ***               * *
       *                 *
图形一：

public class HomeWork8_24 {
    public static void main(String[] args) {
        for (int i = 1; i <= 4; i++) {
            for (int x = 1; x <= 4 - i; x++) {
                System.out.print(" ");
            }
            for (int j = 1; j <= 2 * i - 1; j++) {
                System.out.print("*");
            }
            System.out.println();
        }
        for (int i = 3; i >= 1; i--) {
            for (int x = 1; x <= 4 - i; x++) {
                System.out.print(" ");
            }
            for (int j = 1; j <= 2 * i - 1; j++) {
                System.out.print("*");
            }
            System.out.println();
        }
    }
}

图形二：

public class HomeWork8_24 {
    public static void main(String[] args) {
        for (int i = 1; i <= 5; i++) {
            for (int x = 1; x <= 5 - i; x++) {
                System.out.print(" ");
            }
            for (int j = 1; j <=  i - 1; j++) {
                System.out.print("* ");
            }
            System.out.println();
        }
        for (int i = 4; i >= 1; i--) {
            for (int x = 1; x <= 5 - i; x++) {
                System.out.print(" ");
            }
            for (int j = 1; j <=  i - 1; j++) {
                System.out.print("* ");
            }
            System.out.println();
        }
    }
}

2、打印出1-1000以内的所有“水仙花数”，所谓“水仙花数”是指一个三位数，其各位数字立方和等于该数本身。例如：153是一个“水仙花数”。

public class HomeWork8_24 {
    public static void main(String[] args) {
        for (int i = 100; i <= 999; i++) {
            if ((i % 10)*(i % 10)*(i % 10)+(i/10%10)*(i/10%10)*(i/10%10)+(i/100)*(i/100)*(i/100)==i){
                System.out.println(i);
            }
        }
    }
}

  3、

  ①

 

import java.util.Scanner;
public class HomeWork8_24 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("请随机输入一个数:");
        int num = scanner.nextInt();
        int sum = 0;
        int[] l1 = new int[]{8, 4, 2, 1, 23, 344, 12};
        for (int i = 0; i < l1.length; i++) {
            System.out.println(l1[i]);
            sum += l1[i];
        }
        System.out.println("所有数值的和为：" + sum);
        for (int i = 0; i < l1.length; i++) {
            if (num == l1[i]) {
                System.out.println("数列中包含此数");
                break;
            }
            if(num!=l1[i] && i==(l1.length-1)){
                System.out.println("数列中不包含此数");
            }
        }
        scanner.close();
    }
}

  ②

import java.util.Scanner;
public class HomeWork8_24 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入4家店的价格");
        int[] prices = new int[4];
        int min = 3200;
        for (int i = 0; i < 4; i++) {
            System.out.print("第" + (i + 1) + "家店的价格：");
            prices[i] = scanner.nextInt();
            if (min > prices[i]){
                min = prices[i];
            }
        }
        System.out.println("最低价格是：" + min);
    }
}

  ③

import java.util.Scanner;
public class HomeWork8_24 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入会员本月的消费记录");
        double[] prices = new double[5];
        double sum = 0;
        for (int i = 0; i < 5; i++) {
            System.out.print("请输入第" + (i + 1) + "笔购物金额：");
            prices[i] = scanner.nextDouble();
        }
        System.out.println("序号金额\t\t\t\t\t\t（元）");
        for (int i = 0; i < 5; i++) {
            System.out.println((i + 1) + "\t\t\t\t\t\t" + prices[i]);
            sum += prices[i];
        }
        System.out.println("总金额\t\t\t\t\t" + sum);

    }
}

4、通过键盘输入10个不同的整数，然后实现倒序保存并输出。如输入1，2，3，4，5，倒序后是   5，4，3，2，1并输出。要求用数组实现。遍历 交换

import java.util.Scanner;
public class HomeWork8_24 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int[] l1 = new int[10];
        int[] l2 = new int[10];
        System.out.println("请输入10个不同的整数：");
        for (int i = 0; i < 10; i++) {
            l1[i] = scanner.nextInt();
            l2[9-i] = l1[i];

        }
        for (int i = 0; i < 10; i++) {
            System.out.println(l2[i] + " ");
        }

    }
}

5、通过键盘输入5个整数，将这5个整数按逆时针顺序转动一次后再输出，如输入1，2，3，4，5，逆时针转动一次后，输出2，3，4，5，1。要求用数组实现。遍历插入

import java.util.Scanner;
public class HomeWork8_24 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int[] l1 = new int[5];
        int[] l2 = new int[5];
        System.out.println("请输入5位整数：");
        for (int i = 0; i < 5; i++) {
            System.out.print("第" + (i + 1) + "位整数为：");
            l1[i] = scanner.nextInt();
        }
        for (int i = 0; i < 5; i++) {
            if (i < 4){
                l2[i] = l1[i+1];
            }else {
                l2[i] = l1[4-i];
            }

        }
        for (int i = 0; i < 5; i++) {
            System.out.print(l2[i] + " ");
        }

    }
}

6、有n个人围成一圈，从头开始循环报1-3，报到3的人出局，求最后剩下的那个人。

import java.util.Scanner;
public class HomeWork8_24 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入总人数：");
        int n = scanner.nextInt();
        scanner.close();
        boolean[] in = new boolean[n];//定义一个人是否在圈内的数组，在为true，不在为false;
        for (int i = 0; i < n; i++) {
            in[i] = true;
        }
            int sum = n;//圈内的人数
            int num = 0;//报到的数
            int index = 0;//索引
            while (sum > 1) {
                if (in[index]) {//假定索引为index的人在圈内
                    num++;
                    if (num == 3) {
                        num = 0;
                        in[index] = false;
                        sum--;
                    }
                }
                index++;
                if (index == n) {
                    index = 0; //当索引的值等于n时把0赋值给索引，重新开始循环
                }
            }

        for (int i = 0; i < n; i++) {
            if (in[i]) {
                System.out.println("留下的人为原来的第" + (i + 1) + "个人");
            }
        }
    }
}