C#基础 第七天

 //class Person
    //{
        //利用字段快速生成属性：字段右键，快速操作和重构，选第一个。
        //private string name { get; set; }
        //private int age { get; set; }
        ////这样最简单，字段都省了
        //public double Score { get; set; }
        //public string Name { get => name; set => name = value; }
        //public int Age { get => age; set => age = value; }
        //public void SetName(string n)
        //{
        //    name = n;
        //}
        //public string GetName()
        //{
        //    return name;
        //}
        //属性
        //public string Name
        //{
        //    get
        //    {
        //        return name;
        //    }
        //    set
        //    {
        //        name = value;
        //    }
        //}
        //public int Age
        //{
        //    get
        //    {
        //        return age;
        //    }
        //设置只读属性，set前面加private或者去掉set
        //set
        //{
        //    age = value;
        //}
    //}
    class Tool
        {
        //ref引用参数
            public void ChangeInt(ref int x,ref int y)
            {
                int c = x;
                x = y;
            y = c; Console.WriteLine("x={0},y={1}",x,y);
            }
        public void Sort(int[]arr)
        {
            for (int i = 0; i < arr.Length-1; i++)
            {
                for (int j = i+1; j < arr.Length; j++)
                {
                    if (arr[i]>arr[j])
                    {
                        int temp = arr[i];
                        arr[i] = arr[j];
                        arr[j] = temp;
                    }
                }
            }
        }
        public double Calculate(double x,double y,out double m,out double g)
        {
            double s = x + y;
             m = x - y;
            g = x * y;
            return s;
        }
        //params参数称为可变数组参数，在传参的时候，既可以传递一个数组进来，也可以直接传递数组里面的元素.在形参列表里面，只能有一个params修饰的参数，并且只能放在最后一位，而且必须是一维数组类型
        public int Sum(int a,params int[]arr)
        {
            int sum = 0;
            for (int i = 0; i < arr.Length; i++)
            {
                sum += arr[i];
            }
            return sum;
        }
        }
    //}
   
    class Program
    {
        static void Main(string[] args)
        {
            //Person s = new Person();
            // s.SetName("zhangsan");
            //string p= s.GetName();
            //s.Age = 21;
            //Console.WriteLine(s.Age);
            //值类型的数据在赋值是拷贝赋值，当把实参赋值给形参后，形参的值发生改变，实参的值不会发生改变
            Tool t = new Tool();
            int a = 10, b = 20;
            //t.ChangeInt(a,b);
            //Console.WriteLine("a={0},b={1}",a,b);
            //引用类型在赋值时，两个变量引用同一块内存
            int[] arr = { 6,8,3,2,9,10};
            int[] brr = arr;
            brr[0] = 7;
            t.Sort(arr);
            foreach (var item in arr)
            {
                Console.WriteLine(item);
            }
            Console.WriteLine(arr[0]);//7

            //ref引用参数：用在值类型的参数前面，调用方法时，实参前面也要加ref关键字，当形参发生改变后，实参也会改变，实参要用初始值；
            t.ChangeInt(ref a,ref b);
            Console.WriteLine("a={0},b={1}",a,b);
            //out输出参数，当方法体里面的代码运行完以后，程序跳回到主程序的时候会把out修饰的形参向外赋值给实参，调用方法时，实参前面也要有out关键字。如果一个方法得到多个返回值，可以使用out参数
            double f,g;
            double d = t.Calculate(23.5,56.2,out  f,out g);
            Console.WriteLine("d={0},f={1}",d,f);
            int[] o = { 1,4,6,3,8};
            int[] i = { 3,6,9};
            int sum = t.Sum(3,6,9);
            Console.WriteLine(sum);
            string str = "hello world/bei%jing";
            char[] ch = {' ','/','%' };
            string[] sts=str.Split(ch);
            foreach (var item in sts)
            {
                Console.WriteLine(item);
            }
            Console.ReadKey();
        }
    }