数组和类声明的几种方式

            //数组的声明
            //第一种
            int[] arr1 = null;
            arr1 = new int[3];
            //第二种
            int[] arr2 = new int[3];
            //第三种
            int[] arr3 = new int[3] { 1, 2, 3 };
            //第四种 不设置数组的初始化大小，有数组元素确定
            int[] arr4 = new int[] { 1, 2, 3 };
            //这个是第四种的简化版
            int[] arr5 = { 1, 2, 3 };

            //类声明的几种方式
            Person p1 = new Person();
            p1.Name = "小明1";
            p1.Age = 20;

            Person p2 = new Person() {
                Name = "小明2",
                Age = 19
            };
            Person p3 = new Person{
                Name = "小明3",
                Age = 19
            };

            Person[] arr_p = new Person[] {
                new Person {
                    Name = "小红",
                    Age = 18
                },
                new Person {
                    Name = "小黑",
                    Age = 19
                }
            };