public static double EvaluatePostFixExpression(QueueUsingDoublyLinkedList <string> postfix)
{
StackUsingLinkedList <string> stack = new StackUsingLinkedList <string>();
var count = postfix.Count;
double answer = 0;
for (int i = 0; i < count; i++)
{
if (stack.Count >= 2 && postfix.Peek().Length == 1 && IsOperator(postfix.Peek()[0]) == true)
{
double x = 0;
double y = 0;
if (Double.TryParse(stack.Peek(), out x))
{
x = Convert.ToDouble(stack.Pop());
}
if (Double.TryParse(stack.Peek(), out y))
{
y = Convert.ToDouble(stack.Pop());
}
double result = Calculate(y, postfix.Dequeue()[0], x);
stack.Push(result.ToString());
}
else
{
stack.Push(postfix.Dequeue());
}
}
if (stack.Count != 0)
{
if (double.TryParse(stack.Peek(), out answer) == true)
{
answer = Convert.ToDouble(stack.Pop());
}
else
{
if (stack.Count != 1)
{
stack.Pop();
}
if (double.TryParse(stack.Peek(), out answer) == true)
{
answer = Convert.ToDouble(stack.Pop());
}
}
}
return(answer);
}
private void TbInfix_TextChanged(object sender, TextChangedEventArgs e)
{
QueueUsingDoublyLinkedList <string> temp = InfixToPostfixConverter.ConvertToPostfix(TbInfix.Text);
QueueUsingDoublyLinkedList <string> postfix = new QueueUsingDoublyLinkedList <string>();
var sb = new StringBuilder();
int count = temp.Count;
for (int x = 0; x < count; x++)
{
var y = temp.Dequeue();
postfix.Enqueue(y);
sb.Append(y);
}
TbPostfix.Text = sb.ToString();
TbResult.Text = PostfixEvaluator.EvaluatePostFixExpression(postfix).ToString();
}
public static QueueUsingDoublyLinkedList <string> ConvertToPostfix(string exp)
{
var postfix = new QueueUsingDoublyLinkedList <string>();
StackUsingLinkedList <char> stack = new StackUsingLinkedList <char>();
StringBuilder num = new StringBuilder();
for (int x = 0; x < exp.Length; x++)
{
if (Char.IsDigit(exp[x]) == true)
{
if (x != exp.Length - 1 && (Char.IsDigit(exp[x + 1]) == true || exp[x + 1] == '.' || exp[x + 1] == ','))
{
num.Append(exp[x]);
}
else
{
num.Append(exp[x]);
postfix.Enqueue(num.ToString());
num.Clear();
if (x != exp.Length - 1 && exp[x + 1] == '(')
{
while (!stack.IsEmpty() && IsOperator(stack.Peek()) && GreaterOrEqualPrecedence('*', stack.Peek()) == true)
{
postfix.Enqueue(stack.Pop().ToString());
}
stack.Push('*');
}
}
}
else if (exp[x] == '.')
{
num.Append(exp[x]);
}
else if (exp[x] == '-')
{
if (x == 0 || IsOperator(exp[x - 1]) == true || exp[x - 1] == '(')
{
if (exp.Length != 1 && x != exp.Length - 1 && exp[x + 1] == '(')
{
exp = exp.Substring(0, x + 1) + '1' + exp.Substring(x + 1);
}
num.Append(exp[x]);
}
else
{
while (!stack.IsEmpty() && IsOperator(stack.Peek()) && GreaterOrEqualPrecedence(exp[x], stack.Peek()) == true)
{
postfix.Enqueue(stack.Pop().ToString());
}
stack.Push(exp[x]);
}
}
else if (exp[x] == '(')
{
stack.Push(exp[x]);
}
else if (IsOperator(exp[x]) == true)
{
while (!stack.IsEmpty() && IsOperator(stack.Peek()) && GreaterOrEqualPrecedence(exp[x], stack.Peek()) == true)
{
postfix.Enqueue(stack.Pop().ToString());
}
stack.Push(exp[x]);
}
else if (exp[x] == ')')
{
while (stack.Peek() != '(')
{
postfix.Enqueue(stack.Pop().ToString());
}
stack.Pop();
if (x != exp.Length - 1 && exp[x + 1] == '(')
{
while (!stack.IsEmpty() && IsOperator(stack.Peek()) && GreaterOrEqualPrecedence('*', stack.Peek()) == true)
{
postfix.Enqueue(stack.Pop().ToString());
}
stack.Push('*');
}
}
}
while (!stack.IsEmpty())
{
postfix.Enqueue(stack.Pop().ToString());
}
return(postfix);
}
