#include "stdafx.h"
#include "Stack.h"
#include "DStack.h"
#include <stdio.h>
#include <iostream>
#include <math.h>
using namespace std;

//--- naglowki funckji ---------
double ONP();
double Eval(char, double, double);
double GetNum();
char   GetOper();
void   SkipSpaces();
int    prior( char cOper );
int    IsDigit( char c );
int    IsOper( char cOper );

//=======================================
int main( int argc, char* argv[] )
{
    cout << "\nPodaj wyrazenie bez nawiasow: ";
    cout << "wartosc = " << ONP();

    cout << "\n\n";
    system("PAUSE");
    return 0;
}
//-----------------------
double ONP()
{
  char c;

  StackItem* pHead = NULL;      // wyzerowanie stosu

  DStackItem* pDHead = NULL;        // wyzerowanie stosu

  dpush( &pDHead, GetNum() );


  while (IsOper(c = GetOper()))
  {
          // prior operatora MUSI byc silnie wiekszy od prior szczytu stosu
          while (prior(c) <= prior(top(pHead))) // jeżeli wyższy priorytet to wyrzucam
          {
              double x = dpop(&pDHead);
              dpush(&pDHead, Eval(pop(&pHead), dpop(&pDHead), x));
          }

          push(&pHead, c);

          dpush(&pDHead, GetNum());

  }
  while( !isEmpty(pHead) )
  {
      double x = dpop(&pDHead);
      dpush(&pDHead, Eval(pop(&pHead), dpop(&pDHead), x));
  }
  return dpop(&pDHead);
}
//-----------------------
double GetNum()
{
    char c;
    double  res = 0;

  SkipSpaces();
  while( IsDigit( c=getchar() ) )
    res = res * 10 + (c-'0');
  if (c == '.')
  {
      double coef = 0.1;
      while (IsDigit(c = getchar()))
      {
          res += coef * (c - '0');
          coef *= 0.1;
      }
  }

  ungetc( c, stdin );
  return res;
}
//-----------------------
int IsDigit( char c )
{
  return ( c>='0' ) && ( c<='9' );
}
//------------------------
int  IsOper( char cOper )
{
  switch( cOper )
  {
    case '+':
    case '-':
    case '*':
    case '/':
    case '^':
    case '(':
    case ')': return 1;
    default: return 0;
  }
}
//------------------------
char GetOper()
{
  SkipSpaces();
  return getchar();
}
//------------------------
void SkipSpaces()
{
  char c;
  while( ( c = getchar() ) == ' ' );
  ungetc( c, stdin );
}
//------------------------
int prior( char cOper )
{
  switch( cOper )
  {
    case '(': return 1;
    case '+': ;
    case '-': return 2;
    case '*': ;
    case '/': return 3;
    case '^': return 4;
  }
  return 0;
}
double Eval(char cOper, double arg1, double arg2)
{
    switch (cOper)
    {
    case '+': return arg1 + arg2;
    case '-': return arg1 - arg2;
    case '*': return arg1 * arg2;
    case '/':  if (arg2 != 0)
    {
        return arg1 / arg2;
    }
               else
               {
                   printf("%s,Nie można dzielić przez 0");
                   return 0;
               }
    case '^': return pow(arg1, arg2);

        system("PAUSE");
        return 0;
    }
}