public void Tree_Test()
{
var initialEquation = "3+2*4/5";
var checkPostfix = ShuntingYardAlgorithm.PostfixString(initialEquation);
checkPostfix.Should().Be("324*5/+");
var arithmeticTree = ExpressionTree.BuildArithmeticTree(checkPostfix);
arithmeticTree.Data.Should().Be('+');
}
public void PostfixEvaluatorTest()
{
// 3 + 4 * 5 = 23
var queue = ShuntingYardAlgorithm.ShuntingYard("3+4*5");
PostfixEvaluator.EvaluatePostfix(queue).Should().Be(23);
// 3 * (4 + 5) = 27
queue = ShuntingYardAlgorithm.ShuntingYard("3*(4+5)");
PostfixEvaluator.EvaluatePostfix(queue).Should().Be(27);
}
public void InfixToPostfixTest()
{
var queue = ShuntingYardAlgorithm.ShuntingYard("3+2*4/5");
queue.Dequeue().Should().Be('3');
queue.Dequeue().Should().Be('2');
queue.Dequeue().Should().Be('4');
queue.Dequeue().Should().Be('*');
queue.Dequeue().Should().Be('5');
queue.Dequeue().Should().Be('/');
queue.Dequeue().Should().Be('+');
queue = ShuntingYardAlgorithm.ShuntingYard("3+4*5");
queue.Dequeue().Should().Be('3');
queue.Dequeue().Should().Be('4');
queue.Dequeue().Should().Be('5');
queue.Dequeue().Should().Be('*');
queue.Dequeue().Should().Be('+');
queue = ShuntingYardAlgorithm.ShuntingYard("3*(4+5)");
queue.Dequeue().Should().Be('3');
queue.Dequeue().Should().Be('4');
queue.Dequeue().Should().Be('5');
queue.Dequeue().Should().Be('+');
queue.Dequeue().Should().Be('*');
queue = ShuntingYardAlgorithm.ShuntingYard("3+4*2/(1-5)^2^3");
// 3 4 2 × 1 5 − 2 3 ^ ^ ÷ +
queue.Dequeue().Should().Be('3');
queue.Dequeue().Should().Be('4');
queue.Dequeue().Should().Be('2');
queue.Dequeue().Should().Be('*');
queue.Dequeue().Should().Be('1');
queue.Dequeue().Should().Be('5');
queue.Dequeue().Should().Be('-');
queue.Dequeue().Should().Be('2');
queue.Dequeue().Should().Be('3');
queue.Dequeue().Should().Be('^');
queue.Dequeue().Should().Be('^');
queue.Dequeue().Should().Be('/');
queue.Dequeue().Should().Be('+');
queue = ShuntingYardAlgorithm.ShuntingYard("3-2+1");
queue.Dequeue().Should().Be('3');
queue.Dequeue().Should().Be('2');
queue.Dequeue().Should().Be('-');
queue.Dequeue().Should().Be('1');
queue.Dequeue().Should().Be('+');
}
static void Main(string[] args)
{
while (true)
{
string input = PromptGetResponse(Messages.Prompt_EnterExpression);
if (input.ToLower() == QuitKeyword.ToLower())
{
break;
}
string postfix;
int result;
try
{
postfix = ShuntingYardAlgorithm.Convert(input);
}
catch (Exception)
{
DisplayMessage(Messages.ErrorMessage_PostfixParseFailed, isError: true);
continue;
}
try
{
result = ReversePolishNotation.Evaluate(postfix);
}
catch (Exception ex)
{
// special case in that it's very clear what the problem is
if (ex is DivideByZeroException)
{
DisplayMessage(Messages.ErrorMessage_EvaluationGeneratesDivideByZero, isError: true);
}
else
{
DisplayMessage(Messages.ErrorMessage_EvaluationFailed, isError: true);
}
continue;
}
DisplayMessage($"{Messages.Message_Result} {result}");
}
}
private static void Main()
{
const string infix = "3+2*4/5";
Console.WriteLine($"Initial infix: {infix}");
// 324*5/+
var postfix = ShuntingYardAlgorithm.PostfixString(infix);
Console.WriteLine($"Postfix by Shunting-yard: {postfix}");
var arithmeticTree = ExpressionTree.BuildArithmeticTree(postfix);
Console.WriteLine("Infix by In-Order traversal: ");
DisplayTree.InOrderTraversal(arithmeticTree);
Console.WriteLine();
Console.WriteLine("Postfix notation by Post-Order traversal: ");
DisplayTree.PostOrderTraversal(arithmeticTree);
Console.WriteLine();
Console.WriteLine("Prefix notation by Pre-Order traversal: ");
DisplayTree.PreOrderTraversal(arithmeticTree);
Console.WriteLine();
Console.WriteLine("Infix: ");
ExpressionTree.PrintInfixExpression(arithmeticTree);
}
public void WhenConvert_InvalidExpression_ThrowsException(string input)
{
Assert.ThrowsException <FormatException>(() => ShuntingYardAlgorithm.Convert(input));
}
public void WhenConvert_ValidExpression_Returns_CorrectResult(string input, string expectedOutput)
{
var output = ShuntingYardAlgorithm.Convert(input);
Assert.AreEqual(expectedOutput, output);
}
private void Given(string expression)
{
var test = new ShuntingYardAlgorithm();
_result = test.Transform(expression);
}
