/* valuta.cpp */
/* Program that reads a exchange rates from file currencies.dat:
**   mk     1.0
**   $      5.7
**   ECU    6.5
**   SKr    0.9
**
** Vesa Lappalainen 12.5.1998


========================================
1. Plan the program:
========================================

Hello this .....

Give the amount and valuta >15 $[ret]
15 $ is 85.5 mk
Give the amount and valuta >3 SKr[ret]
3 SKr is 2.1 mk
Give the amount and valuta >6[ret]
6 SKr is 4.2 mk
Give the amount and valuta >[ret]

Good bu....


========================================
2. Plan the files you need:
========================================

currencies.dat:
------------

  mk     1.0
  $      5.7
  SKr    0.7


In this program valuta curses is edited
by some text editor because the lack
of time in examination!

========================================
3. Plan the classes you need:
========================================

Objects: (classes)
===================

cValuta
 - amount : double
 - valuta : string
 -

cCurrencies
 - handles a collection of valuta
 - read the file valuta.dat
 - tells how many mk


cInterface
 - make quiestions
 - read the answer to valuta
 - ask cCurrencies to find the sum
 - display result

========================================
4. Draw the picture of data structures:
========================================
                                 cInteface
                                  ----------
                                  |   $    | valuta_str
                                  | -------|
                                  ||  $   || valuta
          cCurrencies             ||  15  ||
              |---------|         ||------||
    max_size  |    4    |         |        |
    number_of |    3    |<--------+---o    |  currencies
    items     |    o    |         ----------
              -----|-----
                   |
         cValuta   v
              -----------
      valuta  |    mk   |   0
      amount  |    1    |
              -----------
              |    $    |   1
              |    5.7  |
              -----------
              |    Skr  |   2
              |    0.7  |
              -----------
              |         |   3
              |         |
              -----------


========================================
5. Write the program
========================================
*/

#include <stdio.h>
#include <iostream.h>
#include <fstream.h>
#include <iomanip.h>
#include <string>

#define MAX_VALUTAS 20


//------------------------------------------------------------------------------
string separate(string &st, char ch=' ',bool backwards=false)
// Separates from the string two parts from choosen character
// The first part is returned as a function value and the other
// part is in st.  The dircetion the search ch is chosen by the
// flag backwards.
// If there is no ch then the whole string is returned and st = ""
// Example: let we have st and s;
//  1)  st = "123 456";  s = separate(st);   => st == "456"  s == "123"
//  2)  st = "123";      s = separate(st);   => st == ""     s == "123"
//  3)  st = "1 2 3";
//      while ( st != "" ) cout << separate(st) << ",";  => print 1,2,3,
//
{
  size_t p;
  if ( !backwards ) p = st.find(ch); else p = st.rfind(ch);
  string first = st.substr(0,p);
  if ( p == string::npos ) st = "";
  else st.erase(0,p+1);
  return first;
}



//---------------------------------------------------------------------------
class cValuta {
  string valuta;
  double amount;
public:                           // 0123456
  int reset(const string &st) {  // "mk 1.00"
  // if st = "mk 2.00"  => valuta = "mk"  amount = 2.00 , return 0  #1
  // if st = "mk"       => valuta = "mk"  amount = 1.00 , return 1  #2
  // if st = " mk"      => valuta = ""    amount = 1.00 , return 1  #3
  // if st = " "        => valuta = ""    amount = 1.00 , return 1  #4
  // if st = "mk 2.00 " => valuta = "mk"  amount = 2.00 , return 0  #1
    amount = 1.0;
//    char val[100];
//    if ( sscanf(st.c_str(),"%s %lf",val,&amount) != 2 ) return 1;
//    valuta = val;
    string tmp = st;
    valuta = separate(tmp);
    if ( sscanf(tmp.c_str(),"%lf",&amount) != 1 ) return 1;
    return 0;
  }
  int reset(double d,const string &st) {
    amount = d;
    valuta = st;
    return 0;
  }
  cValuta(double d=1.0, const string &st = "mk") { reset(d,st);           }
  cValuta(const string &st)                      { reset(st);             }
  double getAmount()            const            { return amount;         }
  const string &getValuta()     const            { return valuta;         }
  ostream &print(ostream &os) const {
//    cStreamPre pre(os,2);
    os << amount << " " << valuta; return os;
  }
  int operator==(const cValuta &val) const {
    return valuta == val.valuta;
  }
};

ostream &operator<<(ostream &os,const cValuta &valuta) { return valuta.print(os); }

//---------------------------------------------------------------------------
class cCurrencies {
  int max_size;
  int number_of_items;
  cValuta *items;
  int reserve(int size_of) {
    number_of_items = 0; max_size = 0;
    if ( size_of <= 0 ) return 0;
    items = new cValuta[size_of];
    if ( items != NULL ) max_size = size_of;
    return max_size == 0;
  }
public:
  void free() { if ( max_size > 0 ) delete [] items; }
  cCurrencies(int size_of=0) { reserve(size_of);  }
  cCurrencies(const cCurrencies &currencies) { reserve(0); substitute(currencies); }
  ~cCurrencies() { free(); }
  int add(const cValuta &n) {
    if ( number_of_items >= max_size ) return 1;
    items[number_of_items++] = n;
    return 0;
  }
  cCurrencies &substitute(const cCurrencies &currencies);
  cCurrencies &operator=(const cCurrencies &currencies) { return substitute(currencies); }
  int find(const cValuta &item_to_find) const;
  int read();

  const string &valuta(const string &val); // const;
  double multiplier(const cValuta &val) const;
  const string &basic_valuta_name() const { return items[0].getValuta(); }
};


cCurrencies &cCurrencies::substitute(const cCurrencies &currencies)
{
  if ( this == &currencies ) return *this;
  if ( max_size != currencies.max_size ) {
    free(); reserve(currencies.max_size);
  }
  number_of_items = 0;
  for (int i=0; i<currencies.number_of_items; i++)
    add(currencies.items[i]);
  return *this;
}


int cCurrencies::find(const cValuta &item_to_find) const
{
  for (int i=0; i < number_of_items; i++)
    if ( items[i] == item_to_find ) return i;
  return -1;
}


int cCurrencies::read()
{
  ifstream f("currencies.dat");

  if ( !f ) return 1;

  cValuta valuta;
  string line;

  while ( getline(f,line) ) {
    if ( valuta.reset(line) ) break;
    add(valuta);
  }

  return 0;
}


double cCurrencies::multiplier(const cValuta &val) const
{
  int i = find(val);
  if ( i >= 0 ) return items[i].getAmount();
  return 1.0;
}


const string &cCurrencies::valuta(const string &val) // const
{
  static string error("?$?");
  int i = find(cValuta(1.0,val));
  if ( i >= 0 ) return items[i].getValuta();
  return error;
}


//---------------------------------------------------------------------------
class cIntreface {
  cCurrencies *currencies;
  cValuta valuta;
  string valuta_str;
public:
  cIntreface(cCurrencies *val) : currencies(val) { valuta_str[0] = 0; }
  void print() {
    double basic_amount = currencies->multiplier(valuta) * valuta.getAmount();
    cValuta basic_valuta(basic_amount,currencies->basic_valuta_name());
    cout << valuta << " is " << basic_valuta << endl;
  }
  int ask();
};


int cIntreface::ask()
{
  string str; double money;

  cout << "Give the amount and valuta >";  getline(cin,str);  // 15 MK
  if ( str == "" ) return 1;
  if ( str == "quit" ) return 1;

//  sscanf(str.c_str(),"%lf%s",&money,valuta_str);
  string tmp = separate(str);  // tmp = "15", str=MK

  sscanf(tmp.c_str(),"%lf",&money);
  if ( str != "" ) valuta_str = str;

  valuta.reset(money,currencies->valuta(valuta_str)); // 15 mk

  return 0;
}


//---------------------------------------------------------------------------
int main(void)
{
  cCurrencies currencies(MAX_VALUTAS);
  if ( currencies.read() ) { cout << "No file!" << endl; return 1; }
  cIntreface display(&currencies);

  while ( display.ask() == 0 )
    display.print();

  cout << "Thank you!" << endl;
  return 0;
}