feat: ✨ Finish MyReplace

Stream/Program.cs

@@ -1,3 +1,3 @@
 // See https://aka.ms/new-console-template for more information
 
-Console.WriteLine("Hello, World!");
+Stream.Stream.MyReplace("test.txt", 'u', 'a');

Stream/Stream.cs

@@ -7,4 +7,38 @@ public class Stream
     {
         return File.Exists(path);
     }
+
+    public static void MyReplace(string path, char toReplace, char replace)
+    {
+        string preResult = String.Empty;
+        string result = String.Empty;
+        try
+        {
+            using (StreamReader sr = new StreamReader(path))
+            {
+                preResult = sr.ReadToEnd();
+            }
+
+            foreach (var chara in preResult)
+            {
+                if (chara == toReplace)
+                {
+                    result += replace;
+                }
+                else
+                {
+                    result += chara;
+                }
+            }
+
+            using (StreamWriter sw = new StreamWriter(path))
+            {
+                sw.WriteLine(result);
+            }
+        }
+        catch (Exception)
+        {
+            throw new ArgumentException("Error");
+        }
+    }
 }