Added 0344-reverse-string.cs

Author: Dalton-V

csharp/0344-reverse-string.cs

@@ -0,0 +1,12 @@
+public class Solution
+{
+    public void ReverseString(char[] s)
+    {
+        for (int i = 0; i < s.Length / 2; i++)
+        {
+            var temp = s[i];
+            s[i] = s[s.Length - i - 1];
+            s[s.Length - i - 1] = temp;
+        }
+    }
+}