Javase04

        int[] arr = new int[10];
        int brr[] = new int[10];    

public class Demo10 {
    public static void main(String[] args) {
        //01    静态初始化
        int[] a = {1,2,3};
        //02    动态初始化:包含默认初始化
        int[] b = new int[3];
        b[0] = 1;
    }
}

public class Demo11 {

    public static void main(String[] args) {
        int[] arr = {1,2,3,4,5};
        //打印数组元素
        for (int i = 0; i < arr.length; i++) {
            System.out.println(arr[i]);
        }
        //for each
        for (int x:arr) {
            System.out.println(x);
        }
        //接受翻转数组
        int[] crr = fun(arr);
        for (int x:crr) {
            System.out.print(x);
        }

    }
    //翻转数组
    public static int[] fun(int[] arr){
        int[] brr = new int[arr.length];
        for (int i = 0,j = brr.length - 1;i < arr.length;i++,j--){
            brr[j] = arr[i];
        }
        return brr;
    }

}

public class Demo12 {

    public static void main(String[] args) {
        int[] a = {1,23,21,333,123};
        for (int i = 0;i < a.length;i++){
            for (int j = 0;j < a.length - 1 - i;j++){
                if (a[j] > a[j + 1]){
                    int t = a[j];
                    a[j] = a[j + 1];
                    a[j + 1] = t;
                }
            }
        }
        for (int x:a) {
            System.out.println(x);
        }
    }
}

public class Demo13 {

    public static void main(String[] args) {
        //创建一个二维数组11*11
        int[][] arr1 = new int[11][11];
        arr1[1][2] = 1;
        arr1[2][3] = 2;
        //输出原始数组
        System.out.println("输出原始数组：");
        for (int[] a1:arr1) {
            for (int a2:a1) {
                System.out.print(a2 + "\t");
            }
            System.out.println();
        }

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

        //转换为稀疏数组
        //获取有效值个数
        int sum = 0;
        for (int i = 0; i < 11; i++) {
            for (int j = 0; j < 11; j++) {
                if(arr1[i][j] != 0){
                    sum++;
                }
            }
        }
        System.out.println("有效值个数：" + sum);

        //创建一个稀疏数组
        int[][] arr2 = new int[sum + 1][3];
        arr2[0][0] = 11;
        arr2[0][1] = 11;
        arr2[0][2] = sum;

        //遍历数组，把有效值存到稀疏数组
        int count = 0;
        for (int i = 0; i < arr1.length; i++) {
            for (int j = 0; j < arr1[i].length; j++) {
                if (arr1[i][j] != 0){
                    count++;
                    arr2[count][0] = i;
                    arr2[count][1] = j;
                    arr2[count][2] = arr1[i][j];
                }
            }
        }
        System.out.println("=========================================");
        //输出稀疏数组
        System.out.println("稀疏数组：");
        for (int i = 0; i < arr2.length; i++) {
            System.out.println(arr2[i][0] + "\t" + arr2[i][1] + "\t" + arr2[i][2]);
        }

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

        System.out.println("还原：");
        //1.读取稀疏数组
        int[][] arr3 = new int[arr2[0][0]][arr2[0][1]];
        for (int i = 1;i < arr2[0][2] + 1;i++){
            arr3[arr2[i][0]][arr2[i][1]] = arr2[i][2];
        }

        for (int[] a1:arr3) {
            for (int a2:a1) {
                System.out.print(a2 + "\t");
            }
            System.out.println();
        }







    }

}