2022年5月15日【Jiawei

C#的基础教程

https://www.bilibili.com/video/BV1c4411s7UV?p=13
数组的遍历

数组长度获取： 数组名.length;
演示 1： for 语句循环赋值
演示 2： for 语句循环取值

         int[] intArray = new int[] { 11, 22, 33, 44, 55, 66, 77, 88, 99 };
            //遍历数组. ---------------------取值-----------------.
            //intArray.Length : 可以取得当前数组的长度.9.
            //Console.WriteLine(intArray.Length);
            for (int i = 0; i < intArray.Length; i++)
            {
            Console.WriteLine(intArray[i]);
   			}
            Console.ReadKey(); //------- 这一句话的目的是让 界面停住 等待按键输入

        string[] str = new string[5];       //数组的声明与初始化.

           //数组的元素 --------------------- 赋值---------------------.
           for (int i = 0; i < str.Length; i++)
           {
               str[i] = "元素" + i;
           }

           //循环取值.
           for (int j = 0; j < str.Length; j++)
           {
               Console.WriteLine(str[j]);
           }
            Console.ReadKey();

         //例：定义一个字符串数组，存放12 生肖，循环遍历这个数组，将元素组合成一
            //个字符串，且元素与元素之间用’| ’分割。
            //12 生肖数组元素如下："子鼠","丑牛","寅虎","卯兔","辰龙","巳蛇","午马","未羊","申猴","酉鸡","戌狗","亥猪"。

            
            string[] animals = new string[]{"子鼠","丑牛","寅虎","卯兔","辰龙","巳蛇","午马","未羊","申猴","酉鸡","戌狗","亥猪"};
            string animalStr = "";

            for (int i = 0; i < animals.Length; i++)
            {
                animalStr += animals[i];
                if(i < animals.Length - 1)
                {
                    animalStr += "|";
                }
            }

            Console.WriteLine(animalStr);
            Console.ReadKey();

遍历数组的方法

        //foreach 遍历数组.          
            int[] intArray = new int[] { 1, 2, 3, 4, 5, 6, 7, 8, 9 };          
            foreach(int i in intArray)
            {
                Console.WriteLine(i);
            }
            Console.ReadKey();

运行快捷键 F5
进入看代码块快捷键F12

            int[] intArray = new int[5];        //元素默认值:0
            float[] fArray = new float[5];      //元素默认值:0
            double[] dArray = new double[5];    //元素默认值:0
            string[] sArray = new string[5];    //元素默认值:NULL
            bool[] bArray = new bool[5];        //元素默认值:Flase
            //遍历int[]
            foreach(int i in intArray)
            {
                Console.WriteLine(i);
            }
            Console.WriteLine("--------------------------");
            //遍历float[]
            foreach (int f in fArray)
            {
                Console.WriteLine(f);
            }
            Console.WriteLine("--------------------------");
            //遍历double[]
            foreach (int d in dArray)
            {
                Console.WriteLine(d);
            }
            Console.WriteLine("--------------------------");
            //遍历string[]
            foreach (string s in sArray)
            {
                Console.WriteLine(s);
            }
            Console.WriteLine("--------------------------");
            //遍历bool[]
            foreach (bool b in bArray)
            {
                Console.WriteLine(b);
            }
            Console.ReadKey();

---

数值传递 和 引用传递
https://www.bilibili.com/video/BV1c4411s7UV?p=14
数值类型和引用类型

            //1.演示：int 类型变量间传值.
            int a = 10;
            int b = a;  //变量间的传值. b = 10; 值传递.
            b = 20;
            Console.WriteLine("a的值是{0}，b的值是{1}", a, b);  //a:10   b:20   -------输出在一行中
            Console.WriteLine("--------------------------");
            Console.WriteLine("a的值是{0}\r\nb的值是{1}", a, b);  //a:10   b:20 -------分2行输出  加上 \r\n
            Console.ReadKey();

            //演示：int 数组类型变量间传值.
            int[] intA = new int[] { 111, 222, 333, 444 };
            int[] intB = intA; //变量间的传值. 引用.
            intB[0] = 100;
            intB[3] = 999;
            foreach(int i in intA)
            {
                Console.WriteLine(i);
            }
            Console.WriteLine("--------------------------");
            foreach(int j in intB)
            {
                Console.WriteLine(j);
            }
            Console.ReadKey();