添加Lesson23

C#核心/Lesson23_面向对象相关-String练习/Program.cs

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+    namespace Lesson23_面向对象相关_String练习
+{
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            Console.WriteLine("string练习题");
+            #region 练习题一
+            //请写出string中提供的截取和替换对应的函数名
+            string str = "123";
+            str = str.Substring(1);
+            str = str.Substring(1, 1);
+
+            str = "123123";
+            str = str.Replace("123", "哈哈哈");
+            #endregion
+
+            #region 练习题二
+            string str1 = "1|2|3|4|5|6|7";
+            string[] strs = str1.Split('|');
+            str1 = "";
+            for (int i = 0; i < strs.Length; i++)
+            {
+                str1 += int.Parse(strs[i]) + 1;
+                if(i < strs.Length - 1)
+                {
+                    str1 += "|";
+                }
+            }
+            Console.WriteLine(str1);
+            #endregion
+
+            #region 练习题四
+            string strr = null;//开了栈内存1，没开堆内存0
+            strr = "123";//堆内存+1
+            string str2 = strr;//栈内存+1
+            str2 = "321";//堆内存+1
+            str2 += "123";//堆内存+1
+                          // 请问，上面这段代码，分配了多少个新的堆空间
+                          //3个
+            #endregion
+
+            #region 练习题五
+            //编写一个函数，将输入的字符串反转。不要使用中间商，你必须原地修改输入数组。交换过程中不使用额外空间
+            //比如：输入{'h','e','l','l','o'}
+            //输出    {'o','l','l','e','h'}
+
+            Console.WriteLine("请输入内容");
+            string str3 = Console.ReadLine();
+            char[] chars = str3.ToCharArray();
+            for (int i = 0; i < chars.Length / 2; i++)
+            {
+                //交换
+                //char temp = chars[i];
+                //chars[i] = chars[chars.Length - 1 - i];
+                //chars[chars.Length - 1 - i] = temp;
+                chars[i] = (char)(chars[i] + chars[chars.Length - 1 - i]);
+                chars[chars.Length - 1 - i] = (char)(chars[i] - chars[chars.Length - 1 - i]);
+                chars[i] = (char)(chars[i] - chars[chars.Length - 1 - i]);
+            }
+
+            for (int i = 0; i < chars.Length; i++)
+            {
+                Console.Write(chars[i]);
+            }
+
+            str3 = new string(chars);
+            Console.WriteLine(str3);
+            #endregion
+        }
+    }
+}