}//method
public static String toPostfix(String cad)
{
String res = "";
LkStack <char> pila = new LkStack <char>();
char c;
for (int i = 0; i < cad.Length; i++)
{
c = cad.ElementAt(i);
if (char.IsLetterOrDigit(c) || c == '.')
{
res += c;
}
else
{
if (res.Length >= 1)
{
if (res.ElementAt(res.Length - 1) != ' ')
{
res += " ";
}
}
if (c == '(')
{
pila.push(c);
}
else
{
if (c == ')')
{
while (!pila.isEmpty() && pila.peek() != '(')
{
res += pila.pop() + " ";
}
if (!pila.isEmpty() && pila.peek() == '(')
{
pila.pop();
}
}
else
{
while (!pila.isEmpty() && jerarquia(c) <= jerarquia(pila.peek()))
{
res += pila.pop() + " ";
}
pila.push(c);
}
}
}
}
res += " ";
while (!pila.isEmpty())
{
res += pila.pop() + " ";
}
return(res);
}//method
}//method
public static LkStack <string> stringPila(String cadena)
{
String[] aux;
Boolean ayuda;
ayuda = true;
LkStack <string> pila;
int i;
i = 0;
while (i < cadena.Length && ayuda)
{
if (cadena.ElementAt(i) == '+' || cadena.ElementAt(i) == '-' || cadena.ElementAt(i) == '*' || cadena.ElementAt(i) == '/')
{
ayuda = false;
}
i++;
}
pila = new LkStack <string>();
if (ayuda)
{
pila.push(cadena);
Console.WriteLine(pila.peek());
}
else
{
aux = cadena.Split(' ');
for (i = aux.Length - 1; i >= 0; i--)
{
switch (aux[i])
{
case "-":
pila.push("-");
break;
case "+":
pila.push("+");
break;
case "*":
pila.push("*");
break;
case "/":
pila.push("/");
break;
default:
pila.push(aux[i]);
break;
} //switch
} //for
} //else
return(pila);
} //method
}//method
public static double resuelvePf(LkStack <string> expresion)
{
double resp, aux1, aux2;
char oper;
LkStack <string> pila = new LkStack <string>();
resp = Convert.ToDouble(expresion.peek());
while (!expresion.isEmpty())
{
try {
Convert.ToDouble(expresion.peek());
pila.push(expresion.pop());
}
catch
{
aux1 = Convert.ToDouble(pila.pop());
aux2 = Convert.ToDouble(pila.pop());
oper = (expresion.pop().ElementAt(0));
switch (oper)
{
case '+':
resp = aux2 + aux1;
break;
case '-':
resp = aux2 - aux1;
break;
case '*':
resp = aux2 * aux1;
break;
case '/':
resp = aux2 / aux1;
break;
}
string t = "" + resp;
pila.push(t);
}
}
return(resp);
}//method
