第九话-Java数组

数组声明创建

数组初始化

三种初始化

数组内存位置

数组4个基本特点

数组的使用

package com.xie.array;

public class Demo01 {
    public static void main(String[] args) {
        int[] arrays = {1,2,3,4,5};
        for (int i = 0; i < arrays.length; i++) {
            System.out.println(arrays[i]);
        }

        int[] result = new int[arrays.length];
        //反转数组
        for(int i = 0,j=arrays.length-1;i<arrays.length; i++,j--){
            result[j] = arrays[i];
        }
        //取不到下标
        for (int r : result) {
            System.out.println(r);
        }
    }
}

多维数组

package com.xie.array;

public class Demo02 {
    public static void main(String[] args) {
        int[][] arrays = {{1,2},{3,4},{5,6}};
        for (int i = 0; i < arrays.length; i++) {
            for (int j = 0; j < arrays[i].length; j++) {
                System.out.println(arrays[i][j]);
            }
        }
    }
}

Arrays类

package com.xie.array;

import java.util.Arrays;

public class Demo03 {
    public static void main(String[] args) {
        int[] a = {1,23,445,111,33333,42,12};
        //打印
        System.out.println(Arrays.toString(a));
        //排序
        Arrays.sort(a);
        System.out.println(Arrays.toString(a));
        //填充
        Arrays.fill(a,2,4,0);
        System.out.println(Arrays.toString(a));
    }
}

冒泡排序

package com.xie.array;

import java.util.Arrays;

public class Demo04 {
    public static void main(String[] args) {
        int[] a = {1,33,2,334,3333,3,9};
        int temp;
        for (int i = 0; i < a.length-1; i++) {
            for (int j = 0; j < a.length-i-1; j++) {
                if(a[j]>a[j+1]){
                    temp = a[j];
                    a[j] = a[j+1];
                    a[j+1] = temp;
                }
            }
        }
        System.out.println(Arrays.toString(a));
    }
}