将数字一个一个存入数组，将数组转换为数字

1、将数字按一个一个存入数组

        int number = 123456;
        int temp=number;
        //获取数字长度动态初始化数组
        int count = 0;
        while (number != 0) {
            number = number / 10;
            count++;
        }
        int [] arr = new int[count];
        //将数子存入
        int index =arr.length-1;
        while (temp != 0){
            int ge= temp%10;
            arr[index]=ge;
            temp= temp/10;
            index--;
        }
        for (int i : arr) {
            System.out.print(i+" ");
        }

    }

2、将数组转换为数字

        int[] arr = {1, 2, 5, 7, 8, 9};
        int number = 0;
        for (int i = 0; i < arr.length; i++) {
            number = number * 10 + arr[i];
        }
        System.out.println(number);
    }