C# Infix to Postfix Conversion of Multi Digits?

Your logic seems good

Please compare with this one

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Infix
{
class Program
{
static bool InfixToPostfixConvert(ref string infixBuffer, out string postfixBuffer)
{
int priority = 0;
postfixBuffer = "";
Stack s1 = new Stack<char>();
for (int i = 0; i < infixBuffer.Length; i++)
{
char ch = infixBuffer[i];
if (ch == '+' || ch == '-' || ch == '*' || ch == '/')
{
// check the precedence
if (s1.Count <= 0)
s1.Push(ch);
else
{
if (s1.Peek() == '*' || s1.Peek() == '/')
priority = 1;
else
priority = 0;
if (priority == 1)
{
if (ch == '+' || ch == '-')
{
postfixBuffer += s1.Pop();
i--;
}
else
{ // Same
postfixBuffer += s1.Pop();
i--;
}
}
else
{
if (ch == '+' || ch == '-')
{
postfixBuffer += s1.Pop();
s1.Push(ch);
}
else
s1.Push(ch);
}
}
}
else
{
postfixBuffer += ch;
}
}
int len = s1.Count;
for (int j = 0; j < len; j++)
postfixBuffer += s1.Pop();
return true;
}
static void Main(string[] args)
{
string infixBuffer = "";
string postfixBuffer = "";
if (args.Length == 1)
{
infixBuffer = args[0];
InfixToPostfixConvert(ref infixBuffer, out postfixBuffer);
System.Console.WriteLine("InFix :\t" + infixBuffer);
System.Console.WriteLine("PostFix:\t" + postfixBuffer);
}
else
{
infixBuffer = "a+b*c";
InfixToPostfixConvert(ref infixBuffer, out postfixBuffer);
System.Console.WriteLine("InFix :\t" + infixBuffer);
System.Console.WriteLine("PostFix:\t" + postfixBuffer);
System.Console.WriteLine();
infixBuffer = "a+b*c/d-e";
InfixToPostfixConvert(ref infixBuffer, out postfixBuffer);
System.Console.WriteLine("InFix :\t" + infixBuffer);
System.Console.WriteLine("PostFix:\t" + postfixBuffer);
System.Console.WriteLine();
infixBuffer = "a+b*c/d-e+f*h/i+j-k";
InfixToPostfixConvert(ref infixBuffer, out postfixBuffer);
System.Console.WriteLine("InFix :\t" + infixBuffer);
System.Console.WriteLine("PostFix:\t" + postfixBuffer);
System.Console.WriteLine();
}
}
}
}

http://www.softwareandfinance.com/CSharp/Infix_Postfix_Converter.html

2 Replies

Know the answer? Post it — somebody with the same question will find it here.

Muhammad Ahsan5y ago
Finally, Problem Solved

The updated source file is given below which can add floating-point and multi-digit numbers.
Sachin Singh5y ago
Your logic seems good
Please compare with this one
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Infix
{
   class Program
   {
      static bool InfixToPostfixConvert(ref string infixBuffer, out string postfixBuffer)
      {
         int priority = 0;
         postfixBuffer = "";
         Stack s1 = new Stack<char>();
         for (int i = 0; i < infixBuffer.Length; i++)
         {
            char ch = infixBuffer[i];
            if (ch == '+' || ch == '-' || ch == '*' || ch == '/')
            {
               // check the precedence
               if (s1.Count <= 0)
                  s1.Push(ch);
               else
               {
                  if (s1.Peek() == '*' || s1.Peek() == '/')
                     priority = 1;
                  else
                     priority = 0;
                  if (priority == 1)
                  {
                     if (ch == '+' || ch == '-')
                     {
                        postfixBuffer += s1.Pop();
                        i--;
                     }
                     else
                     { // Same
                        postfixBuffer += s1.Pop();
                        i--;
                     }
                  }
                  else
                  {
                     if (ch == '+' || ch == '-')
                     {
                        postfixBuffer += s1.Pop();
                        s1.Push(ch);
                     }
                     else
                        s1.Push(ch);
                  }
               }
            }
            else
            {
               postfixBuffer += ch;
            }
         }
         int len = s1.Count;
         for (int j = 0; j < len; j++)
            postfixBuffer += s1.Pop();
         return true;
      }
      static void Main(string[] args)
      {
         string infixBuffer = "";
         string postfixBuffer = "";
         if (args.Length == 1)
         {
            infixBuffer = args[0];
            InfixToPostfixConvert(ref infixBuffer, out postfixBuffer);
            System.Console.WriteLine("InFix  :\t" + infixBuffer);
            System.Console.WriteLine("PostFix:\t" + postfixBuffer);
         }
         else
         {
            infixBuffer = "a+b*c";
            InfixToPostfixConvert(ref infixBuffer, out postfixBuffer);
            System.Console.WriteLine("InFix  :\t" + infixBuffer);
            System.Console.WriteLine("PostFix:\t" + postfixBuffer);
            System.Console.WriteLine();
            infixBuffer = "a+b*c/d-e";
            InfixToPostfixConvert(ref infixBuffer, out postfixBuffer);
            System.Console.WriteLine("InFix  :\t" + infixBuffer);
            System.Console.WriteLine("PostFix:\t" + postfixBuffer);
            System.Console.WriteLine();
            infixBuffer = "a+b*c/d-e+f*h/i+j-k";
            InfixToPostfixConvert(ref infixBuffer, out postfixBuffer);
            System.Console.WriteLine("InFix  :\t" + infixBuffer);
            System.Console.WriteLine("PostFix:\t" + postfixBuffer);
            System.Console.WriteLine();
         }
      }
   }
}
http://www.softwareandfinance.com/CSharp/Infix_Postfix_Converter.html