static void Main()
{
try
{
string expression = Console.ReadLine();
double[] numbers = expression.Split('+', '-', '*', '/').Select(double.Parse).ToArray();
string operatorsString = "+-*/";
char[] operators = expression.Where(c => operatorsString.Contains(c)).ToArray();
ParsedExpression parsedExpression = new ParsedExpression
{
numbers = numbers,
operators = operators
};
parsedExpression = CalculateMultiplicationAndDivision(parsedExpression);
double result = CalculateAdditionAndSubtraction(parsedExpression);
Console.WriteLine($"{expression} = {result:f2}");
}
catch (FormatException fe)
{
Console.WriteLine(fe.GetType() + ": " + fe.Message);
}
catch (DivideByZeroException dbze)
{
Console.WriteLine(dbze.GetType() + ": " + dbze.Message);
}
}
private static ParsedExpression CalculateMultiplicationAndDivision(ParsedExpression parsedExpression)
{
Queue <double> numbers = new Queue <double>(parsedExpression.numbers);
Queue <char> operators = new Queue <char>(parsedExpression.operators);
Stack <double> newNumbers = new Stack <double>();
Stack <char> newOperators = new Stack <char>();
newNumbers.Push(numbers.Dequeue());
while (numbers.Count > 0)
{
double number = numbers.Dequeue();
char @operator = operators.Dequeue();
if (@operator == '*')
{
double previousNumber = newNumbers.Pop();
newNumbers.Push(previousNumber * number);
}
else if (@operator == '/')
{
if (number == 0)
{
throw new DivideByZeroException();
}
double previousNumber = newNumbers.Pop();
newNumbers.Push(previousNumber / number);
}
else
{
newNumbers.Push(number);
newOperators.Push(@operator);
}
}
parsedExpression.numbers = newNumbers.Reverse().ToArray();
parsedExpression.operators = newOperators.Reverse().ToArray();
return(parsedExpression);
}
private static double CalculateAdditionAndSubtraction(ParsedExpression parsedExpression)
{
double[] numbers = parsedExpression.numbers;
char[] operators = parsedExpression.operators;
double result = numbers[0];
for (int i = 1; i < numbers.Length; i++)
{
char operation = operators[i - 1];
double nextNumber = numbers[i];
if (operation == '+')
{
result += nextNumber;
}
else if (operation == '-')
{
result -= nextNumber;
}
}
return(result);
}