Dfyjkt

My calculator works almost perfect without brackets (it has some bugs). This calculator can do multiple operations (ex. 12+345*2-100 //602).
I want the brackets and the string inside them to be replaced with the result in and then continue with the calculations.
How can i fix the method for the brackets so it works as intended?

Steps for calculations:

1. Finds an symbol


2. Finds the numbers around the symbol


3. Makes calculations and replaces numbers and symbol with the result in the string


4. Checks for any symbols and starts again if there are any


5. 
   

   Gives the result of the mathematical problem

   
   
   

   //Finds numbers around an symbol
   static void FindNumbers(string equation, int start, char symbol)
   
    number1 = 0;
    number2 = 0;
    number1String = string.Empty;
    number2String = string.Empty;
   
    if (equation[start] == symbol)
    
    for (int j = start - 1; j >= 0; j--)//Finds left number around the symbol
    
    if (char.IsDigit(equation[j]))
    
    number1String = equation[j] + number1String;
    
    else
    
    break;
    
    
    for (int j = start + 1; j < equation.Length; j++)//Finds right number around the symbol
    
    if (char.IsDigit(equation[j]))
    
    number2String += equation[j];
    
    else
    
    break;
    
    
    number1 = int.Parse(number1String);
    number2 = int.Parse(number2String);
    
    return;
   
   
   //Devision and Multiplication
   static void Priority1(string equation, int start)
   
    for (int i = start; i < equation.Length; i++)//Multiplication
    
    if (equation[i] == '*')
    
    symbol = equation[i];
    FindNumbers(equation, i, symbol);
   
    currentresult = number1 * number2;
   
    equation = equation.Replace(number1.ToString() + symbol + number2.ToString(),
    currentresult.ToString());
    
    
    for (int i = 0; i < equation.Length; i++)//Devision
    
    if (equation[i] == '/')
    
    symbol = equation[i];
    FindNumbers(equation, i, symbol);
   
    currentresult = number1 / number2;
   
    equation = equation.Replace(number1.ToString() + symbol + number2.ToString(),
    currentresult.ToString());
    
    
    Priority2(equation, 0);
   
   
   //Addition and Devision
   static void Priority2(string equation, int start)
   
    for (int i = start; i < equation.Length; i++)//Addition
    
    if (equation[i] == '+')
    
    symbol = equation[i];
    FindNumbers(equation, i, symbol);
   
    currentresult = number1 + number2;
   
    equation = equation.Replace(number1.ToString() + symbol + number2.ToString(),
    currentresult.ToString());
    
    
    for (int i = 0; i < equation.Length; i++)//Devision
    
    if (equation[i] == '-')
    
    symbol = equation[i];
    FindNumbers(equation, i, symbol);
   
    currentresult = number1 - number2;
   
    equation = equation.Replace(number1.ToString() + symbol + number2.ToString(),
    currentresult.ToString());
    
    
    for (int i = 0; i < equation.Length; i++)//Checks if there are more symbols in the string
    
    if (char.IsSymbol(equation[i]))
    
    Priority1(equation, 0);
    
    
    tempresult = equation;
    Console.WriteLine("Result : " + equation);
   
   
   //Brackets
   static void Brackets(string equation, int index)
   
    for (int i = index; index < equation.Length; index++)
    
    if (equation[index] == '(')
    
    index += 1;
    Brackets(equation, index);
   
    for (int j = index; j < equation.Length; j++)
    
    if (equation[j] == ')')
    
    tempresult = temp;
    Console.WriteLine("..." + tempresult);
    break;
    
    temp += equation[j];
    
   
    Priority1(tempresult, index);
    equation = equation.Replace('(' + temp.ToString() + ')', tempresult.ToString());
    Console.WriteLine("." + equation);
    
    
    Priority1(equation, 0);
   
   
   static void Main(string args)
   
    equation = Console.ReadLine();
   
    Brackets(equation, 0);
    Console.ReadKey();
   
   

   
   

Your code right now theoretically knows how to parse and evaluate correct simple mathematical expressions. By simple expressions I’m referring to expressions made up only of known unary and binary operators and numbers (no parenthesizes)

The expression you are now attempting to parse is either:

1. A simple expression


2. A parenthesized expression


3. A complex expression made up of simple expressions and parenthesized expressions

If its case #1, then you already know how to handle it; parse it and you are finished.

If it’s case #2 the simply remove the parenthesis and parse the expression within.

If it’s case #3 then you take the expressions inside the top level parenthesizes and parse them; you will either be in step 1 or 2 or 3 and hey! Guess what? You already know how to handle those.

Eventually you’ll end up breaking down your expression into only simple expressions. Then you simply need to backtrack evaluating on the way back.

In plain English, you need a recursive parser; a parser that can call itself and parse and evaluate nested expressions.

Consider for example:

e0: 1 + (2 * (3 - 2))

1. e0: You parse 1 + p0
   


2. p0: You parse 2 * p1
   


3. p1: You parse 3 - 2


4. You’re done parsing


5. p1: evaluates to 1
   


6. p0: evaluates to 2
   


7. e0: evaluates to 3
   


8. You’re finished.

Cool thing about this is that the parser can handle, theoretically, infinite nested expressions... the problem is that your computer probably can’t.

You may want to look into breaking the String equation into separate tokens and use something like the Shunting-Yard-Algorithm to parse/calculate the result.