面向对象的复习_封装

封装
字段:存储数据,访问修饰符应该设置为private私有的

string _name;

属性:保护字段,对字段的取值和赋值进行限定

public string Name
{
    get { return _name; }
    set { _name = value; }
}

构造函数:初始化对象,当创建对象的时候会调用构造函数

public Person(string name)
{
    this.Name = name;           
}

new关键字:

Person p = new Person();

1.在堆中开辟空间

2.在开辟的空间中创建对象

3.调用对象的构造函数

this关键字:

1.代表当前类的对象

2.调用自己的构造函数

    class Person
    {
        //字段 属性 构造函数 方法 接口
        string _name;//字段
        public string Name//属性
        {
            get { return _name; }
            set//限定_name的值
            {
                if (value != "张三")
                {
                    value = "张三";
                }
                _name = value;
            }
        }
        int _age;
        public int Age
        {
            get//限定_age的取值范围
            {
                if (_age < 0 || _age > 100)
                {
                    return _age = 0;
                }
                return _age;
            }
            set { _age = value; }
        }
        char _gender;
        public char Gender
        {
            get { return _gender; }
            set { _gender = value; }
        }
        int _chinese;
        public int Chinese
        {
            get { return _chinese; }
            set { _chinese = value; }
        }
        int _math;
        public int Math
        {
            get { return _math; }
            set { _math = value; }
        }
        int _english;
        public int English
        {
            get { return _english; }
            set { _english = value; }
        }
        //构造函数
        public Person(string name, int age, char gender, int chinese, int math, int english)
        {
            this.Name = name;
            this.Age = age;
            if (gender != '男' && gender != '女')//对字段的取值进行限定
            {
                gender = '男';
            }
            this.Gender = gender;
            this.Chinese = chinese;
            this.Math = math;
            this.English = english;
        }

        //通过this调用自身的构造函数
        public Person(string name, int age, char gender)
            : this(name, age, gender, 0, 0, 0)
        {
            this.Name = name;
            this.Age = age;
            this.Gender = gender;
        }


        public void SayHello()
        {
            Console.WriteLine("{0}------{1}-----{2}", this.Name, this.Age, this.Gender);
        }
    }