View difference between Paste ID: qFaiZjWX and mrNzynXV

 public static class BracketsChecker {
 
-	public class BracketMismatchException : ApplicationException {
+	public class BracketErrorException : ApplicationException {
 
 		public BracketErrorException(string message)
 		: base(message) {
 		}
 
 	}
 
 	public class BracketMismatchException : BracketErrorException {
 
 		public readonly char openChar;
 		public readonly char closeChar;
 		public readonly int closePosition;
 
 		public BracketMismatchException(char openChar, char closeChar, int closePosition)
-	public class ExtraOpeningBracketException : ApplicationException {
+
 			this.openChar = openChar;
 			this.closeChar = closeChar;
 			this.closePosition = closePosition;
 		}
 
 	}
 
-	public class ExtraClosingBracketException : ApplicationException {
+	public class ExtraOpeningBracketException : BracketErrorException {
 
 		public ExtraOpeningBracketException()
 		: base("Extra opening bracket") {
 		}
 
 	}
 
 	public class ExtraClosingBracketException : BracketErrorException {
 
 		public readonly char closeChar;
 		public readonly int closePosition;
 
 		public ExtraClosingBracketException(char closeChar, int closePosition)
 		: base(string.Format("Extra closing bracket at {1}: \"{0}\"", closeChar, closePosition)) {
 			this.closeChar = closeChar;
 			this.closePosition = closePosition;
 		}
 
 	}
 
 	private class Bracket {
 
 		char[] openChars;
 		char[] closeChars;
 
 		public Bracket(char[] openChars, char[] closeChars) {
 			this.openChars = openChars;
 			this.closeChars = closeChars;
 		}
 
 	}
 
 	private static readonly Bracket[] Brackets = new[] {
 		new Bracket(new[] { '(' }, new[] { ')' }),
 		new Bracket(new[] { '[' }, new[] { ']' }),
 		new Bracket(new[] { '{' }, new[] { '}' }),
 	}
 
 	private static readonly Dictionary<char, Bracket> BracketsByOpenChar =
 		(
 			from bracket in Brackets
 			from openChar in bracket.openChars
 			select new KeyValuePair<char, Bracket>(openChar, bracket)
 		).ToDictionary();
 
 	private static readonly HashSet<char> CloseChars =
 		new HashSet<char>(
 			from bracket in Brackets
 			from closeChar in bracket.CloseChars
 			select closeChar
 		);
 
 	public static void CheckString(string str) {
 		Stack<Bracket> currentState = new Stack<Bracket>();
 		for(int i=0; i<str.length; i++) {
 			if(BracketsByOpenChar.ContainsKey(str[i])) {
 				currentState.Push(BracketsByOpenChar[str[i]]);
 			} else if(CloseChars.Contains(str[i])) {
 				if(currentState.IsEmpty) {
 					throw new ExtraClosingBracketException();
 				}
 				if(!currentState.Peek().closeChars.Contains(str[i])) {
 					throw new BracketsMismatchException();
 				}
 				currentState.Pop();
 			}
 		}
 		if(!currentState.IsEmpty) {
 			throw new ExtraOpeningBracketException();
 		}
 	}
 
 }