数组的初始化以及应用

一维数组定义：

数据类型 [] 数组名=new 数据类型[数组长度];

int[] array=new int[5];

数据类型[] 数组名={数组内容};

String[] arrays={"zhangsan","lisi","wangwu"};

数组：
在内存中创建一片区域，用来存储长度为10的数组的空间
如果声明了数组空间，则该数组的每一个元素都是该数组类型的“零值”

数组：在内存中创建一篇区域，用来存储长度为10的数组的空间，如果声明了数组空间，则该数组的每一个元素都是该数组类型的“零值”;

例如：

int 的零值 0

double 的零值 0.0

boolean 的零值 false

示例如下：

public class Demo01 {

    public static void main(String[] args) {
        int[] array=new int[10];
        array[0]=100;
        for (int i : array) {
            System.out.print(i+" ");
        }

        System.out.println("+++++++++++++++++++");


        boolean[] booleans=new boolean[3];

        for (boolean aBoolean : booleans) {
            System.out.println(aBoolean);
        }


        System.out.println("++++++++++++++++++++");


        double[] array1=new double[10];
        array1[0]=99;
        System.out.println(array1[0]);

        System.out.println("++++++++++++++++");





    }
}

产生随机数放到数组当中充当数组的内容：

import java.util.Random;

public class Demo02 {
    public static void main(String[] args) {
        int[] arrays=new int[10];
        for (int i = 0; i < arrays.length; i++) {
            arrays[i]= new Random().nextInt(10)+1;
        }

        /**
         * 使用增强for循环
         */
        for (int array : arrays) {
            System.out.print(array+" ");
        }
    }
}

数组元素的拷贝和加和运算

public class Demo03 {
    public static void main(String[] args) {

        double[] array=new double[9];
        double[] array1={3,342,52,23,42,1,34};
        for (double v : array) {
            System.out.print(v+"\t");
        }
        System.out.println();
        System.out.println("+++++++++++++++++");
        for (double v : array1) {
            System.out.print(v+"\t");
        }
        /**
         * 数组的拷贝
         */
        for (int i = 0; i < array1.length; i++) {

            array[i]=array1[i];
        }
        System.out.println();
        for (double v : array) {
            System.out.print(v+" ");
        }
        /**
         * 数组元素的加和
         */
        System.out.println();
        int sum=0;
        for (int i = 0; i < array1.length; i++) {
            sum+=array1[i];
        }
        System.out.println(sum);

        System.out.println();




    }
}

二维数组：

array=new type[][]{值 1,值 2,值 3,…,值 n};
array=new type[][]{new 构造方法(参数列),…};
type[][] array={{第1行第1列的值,第1行第2列的值,…},{第2行第1列的值,第2行第2列的值,…},…};

代码实例如下：

public class Demo04erweiArray {

    public static void main(String[] args) {
        int[][] array=new int[][]{{23,34},{3,23},{4,12},{43,48}};
        for (int i = 0; i < array.length; i++) {
            for (int j = 0; j < array[i].length; j++) {
                System.out.print(array[i][j]+" ");
            }
            System.out.println();
        }
    }
}

俄罗斯方块的打印：

package Weeks02.days04_qianfeng;
import java.util.Random;
public class Demo06 {

    public static void main(String[] args) {
        printeluosifangkuai(getshaps());
    }

    public static void printeluosifangkuai(int[][] shapes){
        for (int i = 0; i < shapes.length; i++) {
            for (int j = 0; j < shapes.length; j++) {
                boolean flag=false;
                for (int k = 0; k < shapes.length; k++) {
                    if (shapes[k][0]==i && shapes[k][1]==j){
                        flag=true;
                        break;
                    }
                }
                if (flag)
                System.out.print("■ ");
                else
                    System.out.print("□ ");
            }
            System.out.println();
        }

    }
    public static int[][] getshaps(){
        Random random=new Random();
        int shaps = random.nextInt(6);
        int type = random.nextInt(3);
        int[][] shap=new int[4][2];

        switch (shaps){
            case 0://方块
                shap=new int[][]{ { 0, 0 }, { 1, 0 }, { 0, 1 }, { 1, 1 } };
                break;
            case 1://横条
                switch (type){
                    case 0:
                    case 2:
                        shap=new int[][]{ { 0, 0 }, { 0, 1 }, { 0, 2 }, { 0, 3 } };
                        break;
                    default:
                        shap=new int[][]{ { 0, 0 }, { 1, 0 }, { 2, 0 }, { 3, 0 } };
                        break;
                }
                break;
            case 2://Z
                switch (type){
                    case 0:
                        shap=new int[][]{{0,0},{0,1},{1,1},{1,2}};
                        break;
                    case 1:
                        shap=new int[][]{{0,2},{0,3},{1,1},{1,2}};
                        break;
                    case 2:
                        shap=new int[][]{{0,0},{1,1},{1,0},{2,1}};
                        break;
                    default:
                        shap=new int[][]{{2,0},{2,1},{1,1},{3,0}};
                    break;
                }
                break;
            case 3://L
                switch (type){
                case 0:
                    shap=new int[][]{{0,0},{1,0},{2,0},{2,1}};
                    break;
                case 1:
                    shap=new int[][]{{0,0},{0,1},{1,0},{2,0}};
                    break;
                case 2:
                    shap=new int[][]{{0,0},{0,1},{1,2},{0,2}};
                    break;
                default:
                    shap=new int[][]{{0,0},{0,1},{1,0},{0,2}};
                    break;
            }
            break;
            default:
                switch (type){
                    case 0:
                        shap=new int[][]{ { 0, 0 }, { 0, 1 }, { 0, 2 }, { 1, 1 } };
                        break;
                    case 1:
                        shap=new int[][]{ { 0, 1 }, { 1, 0 }, { 1, 1 }, { 2, 1 } };
                        break;
                    case 2:
                        shap=new int[][]{ { 0, 1 }, { 1, 0 }, { 1, 1 }, { 1, 2 } };
                        break;
                    default:
                        shap=new int[][]{ { 0, 0 }, { 1, 0 }, { 2, 0 }, { 1, 1 } };
                        break;
                }
                break;



        }
        return shap;
    }
}