Stacks: Help!!!

[Thelastairbender]

---

Mabuang ko sa amo exercise run...2 weeks na gyud ko nag trabaho ani di gyud na ko ma imagine unsaon...palihug kug tabang guyz...c# console application ra ni siya..not asking for spoon feed help pero pls guide me lang on the right track..hehehe

ang problem is ang user mo input ug mathematical expression like 78-93*62-87..dayun isud kuno tanang elements sa stack dayun iyang i compute ang result...mabuang gyud ko..unsaon man kuno nag tell sa program kung unsa ang number and unsa ang operations...ahhh kalibug...patabang lang ko guyz hap

[doomsweek]

This might help: Reverse Polish notation - Wikipedia, the free encyclopedia

[Deathnote]

stacks pud amo lesson run...kana man nang FILO noh? suwayan nya nko solve bai

[Thelastairbender]

waaa nag nose bleed ko anang reverse polish notation..dili man guro na magamit dri na program sir....or wala gyud ko kasabot sa ako gibasa...hehehe...walay mas simple dra na explanation? pero tnx bitaw sir for d info

[nullpointer]

Mabuang ko sa amo exercise run...2 weeks na gyud ko nag trabaho ani di gyud na ko ma imagine unsaon...palihug kug tabang guyz...c# console application ra ni siya..not asking for spoon feed help pero pls guide me lang on the right track..hehehe

ang problem is ang user mo input ug mathematical expression like 78-93*62-87..dayun isud kuno tanang elements sa stack dayun iyang i compute ang result...mabuang gyud ko..unsaon man kuno nag tell sa program kung unsa ang number and unsa ang operations...ahhh kalibug...patabang lang ko guyz hap

using System;
using System.Collections.Generic;
using System.Text;
using System.Collections;

namespace ConsoleCalc
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.Write("Input Expression:");
            string input = Console.ReadLine();
            Calculate(input);
            Console.ReadLine();
        }

        private static void Calculate(string input)
        {
            Decimal answer, currNum = 0;
            string operand;
            const string operators = "+-*/";
            Stack revStack = new Stack();
            Stack stack = new Stack();

            if (input.Length == 0) // ignore if no input
                return;

            char[] temp = input.ToCharArray();
            string str = "";
            int i = 0;
            int len = temp.Length;
            foreach (char ch in temp)
            {
                if (Char.IsDigit(ch)) //is digit?
                {
                    str += ch.ToString(); // store the digits temporarily, for multi-digits
                    if (i == len - 1) // is this the last?
                    {
                        stack.Push(str); // yes, push it.
                    }
                        
                }
                else
                {
                    // if the next char is not digit, probably operator, push your temp digits.
                    stack.Push(str); 
                    str = ""; // clear temp
                    if (operators.Contains(ch.ToString()))  // is token an operator?
                        stack.Push(ch);          // yes, push it
                }
                i++;
            }

            // reverse the stack! it's upside down!!!
            while (stack.Count > 0)
                revStack.Push(stack.Pop());

            // revStack is now in left to right order,
            // top of stack to bottom. assign it to stack!
            stack = revStack;

            // calculate

            // get the top of stack number. proper data validation
            // would check each of the stack pops for expected token
            // Use TryParse().
            answer = Decimal.Parse(stack.Pop().ToString());

            while (stack.Count > 0)
            {
                operand = stack.Pop().ToString();
                currNum = Decimal.Parse(stack.Pop().ToString());

                //1+2
                answer = Arithmetic(answer, operand, currNum);
            }

            Console.WriteLine("The answer is " + answer.ToString() + ".");
        }

        private static Decimal Arithmetic(Decimal a, string oper, Decimal b)
        {
            Decimal result = 0;

            switch (oper)
            {
                case "+":
                    result = a + b;
                    break;

                case "-":
                    result = a - b;
                    break;

                case "*":
                    result = a * b;
                    break;

                case "/":
                    result = a / b;
                    break;

                default:
                    break;
            }

            return result;
        }
    }
}

[Thelastairbender]

waaa...sir gi suwayan nko it works pero it doesnt follow the mdas rule...like if the expression is 3+5*4 32 man iya i answer T.T...need more help guyz but thank you sir null

[nullpointer]

that code evaluates expressions the same as the typical calculator like the windows calculator...you can rewrite your expression to 5*4+3...