#include <iostream.h>
#include <graphics.h>
#include <conio.h>
#include <stdlib.h>
#define MAXCOLS 80
				//NOTACION POSFIJA
struct stack
{
	int top;
	char items[MAXCOLS];
	}ps;
int empy (struct stack *ps)
{
	if (ps->top==-1)
	return 1;
	else
	return 0;
}
int push (struct stack *ps, int x)
{
	ps->items[++(ps->top)]=x;
	return 1;
	}
int pop (struct stack *ps)
{
	if (empty(ps))
	{
	cout<<"\n SUBDESBORDE";
	exit (1);
	}
	return (ps->items[ps->top--]);
	}
	int isoperand (char symb)
	{
	switch (symb)
		{
	  case '+': return 1;
	  case '-': return 1;
	  case '*': return 1;
	  case '/': return 1;
	  default:
		return 0;
	  }
	}
	void popandtest (struct stack *ps, char *px, int *pund)
	{
	if (empty(ps))
	{
	  *pund=1;
	  return;
	  }
	  *pund=0;
	  *px=ps->items [ps->top--];
	  return;
	  }
	void postfix (char infix[], char postr[])
	{
	   int position, und;
	   int outpos=0;
	   char topsymb='+';
	   char symb;
	   struct stack opstk;
	   opstk.top=-1;
	   for (position=0;(symb=infix[position])!='\0';position++)
	   {
	   if (isoperand(symb))
	      postr[outpos++]=symb;
	      else
	      {
	   popandtest(&opstk,&topsymb,&und);
	   while (!und)
	   {
	   postr[outpos++]=topsymb;
	   popandtest(&opstk,&topsymb,&und);
	   }
	if (!und)
	push(&opstk,topsymb);
	if (und || (symb !=')'))
	push(&opstk,symb);
	else
		topsymb=pop(&opstk);
		}
	while (!empty(&opstk))
		postr[outpos++]=pop (&opstk);
	postr[outpos++]='\0';
	return;
	}
}
main ()
{
	char infix[MAXCOLS];
	char postr[MAXCOLS];
	int pos=0;
	cout<<"Dame la Notacion ";
	infix[--pos]= '\0';
	pos=0;
	while (infix[pos]!='\0')
		cout<<"La expresion original es: "<<infix;
		postfix(infix,postr);
		cout<<"\n"<<postr;
		getch ();
		return 0;
		}