static void Main(string[] args)
{
Console.WriteLine("Welcome!\nOperations you can use: * / - + ()");
ValidInput input = new ValidInput();
if (input.isValid)
{
Console.WriteLine("result:\n" + (NormalExpression.Parse(input.input)).ToPreFixed().GetValue());
}
else
{
Console.WriteLine("invalidInput");
}
}
public static new NormalExpression Parse(string input)
{
var exp = new NormalExpression();
bool isPrevOperator = true;
int index = 0;
string[] strings = Regex.Split(input, @"[-+*/()]");
foreach (char item in input)
{
switch (item)
{
case '+':
exp.items.Push(new Item(new Plus()));
isPrevOperator = true;
break;
case '-':
exp.items.Push(new Item(new Minus()));
isPrevOperator = true;
break;
case '*':
exp.items.Push(new Item(new Multiplicator()));
isPrevOperator = true;
break;
case '/':
exp.items.Push(new Item(new Divisor()));
isPrevOperator = true;
break;
case ')':
exp.items.Push(new Item(new OpenningParentheses()));
isPrevOperator = true;
break;
case '(':
exp.items.Push(new Item(new ClosingParentheses()));
isPrevOperator = true;
break;
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
case '.':
if (isPrevOperator)
{
for (; index < strings.Length; index++)
{
if (strings[index].Length != 0)
{
break;
}
}
var valid = double.TryParse(strings[index], out var doub);
if (valid)
{
exp.items.Push(new Item(doub));
}
index++;
}
isPrevOperator = false;
break;
}
}
return(exp);
}