Exercise
Queue Stack Reverse Polish Notation
Objetive
Create a program that reads a Reverse Polish Notation expression from a text file, for example:
3 4 6 5 - + * 6 +
(Result 21)
Each item will be stored in a queue. Once the queue has all the items stored, you will need to transfer them from the queue to a stack using the Queue and Stack classes provided in C#.
Finally, you will operate with the stack to get the correct result of the RPN expression and show it on the console.
Example Code
using System;
using System.Collections.Generic;
using System.IO;
using System.Collections;
namespace FileTextQueue
{
class Program
{
static void Main(string[] args)
{
Console.Write("Introduce el nombre del archivo: ");
string nombreFichero = Console.ReadLine();
if (!File.Exists(nombreFichero))
{
Console.Write("El archivo no existe");
return;
}
try
{
bool depurando = true;
StreamReader ficheroTexto;
ficheroTexto = File.OpenText(nombreFichero);
string line = " ";
Queue micola = new Queue();
do
{
line = ficheroTexto.ReadLine();
if (line != null)
micola.Enqueue(line);
}
while (line != null);
ficheroTexto.Close();
Stack miPila = new Stack();
int numero1 = 0, numero2 = 0;
int cantidadCola = micola.Count;
string valorCola;
string[] valores_linea;
for (int i = 0; i < cantidadCola; i++)
{
valorCola = (string)micola.Dequeue();
valores_linea = valorCola.Split(' ');
for (int c = 0; c < valores_linea.Length; c++)
{
switch (valores_linea[c])
{
case "+":
numero1 = Convert.ToInt32(miPila.Pop());
numero2 = Convert.ToInt32(miPila.Pop());
miPila.Push(numero2 + numero1);
break;
case "-":
numero1 = Convert.ToInt32(miPila.Pop());
numero2 = Convert.ToInt32(miPila.Pop());
miPila.Push(numero2 - numero1);
break;
case "*":
numero1 = Convert.ToInt32(miPila.Pop());
numero2 = Convert.ToInt32(miPila.Pop());
miPila.Push(numero2 * numero1);
break;
case "/":
numero1 = Convert.ToInt32(miPila.Pop());
numero2 = Convert.ToInt32(miPila.Pop());
miPila.Push(numero2 / numero1);
break;
default:
// Almacenamos valores enteros
miPila.Push(valores_linea[c]);
break;
}
}
for (int j = 0; j < miPila.Count; j++)
{
Console.WriteLine(miPila.Pop());
}
}
if (depurando)
Console.ReadLine();
}
catch (Exception e)
{
Console.WriteLine("Error, " + e.Message);
}
}
}
}