#include "apvector.h"
#include "apstring.h"
#include <ctype.h>
#include <iostream.h>

template class apvector<char>;

const int MINLEN = 5;
const int MAXLEN = 15;

class Code
{
    public:
      Code();                   // length is 0, capacity is MAXLEN chars
      Code(const apstring & s); // code has chars in s, length is s.length()
      bool IsValid();           // returns true if code is valid, else false
      int  Length();            // returns # characters in the code
      void AppendCheckSum();    // adds appropriate check sum

      // other functions not shown

      void print(ostream & os) const;
    
    private:
      int myLength;            // # characters in code
      apvector<char> myChars;  // the characters in the code
};

ostream& operator << (ostream& os, const Code & s)
{
    s.print(os);
    return os;
}


int digitToInt(char d)
// precondition:  isdigit(d) == true
// postcondition: returns the value 0 to 9 corresponding
//                to character d
{
    return d - '0';
}

char intToDigit(int val)
// precondition: 0 <= val <= 9
// postcondition: returns the character from
//                '0'..'9' corresponding to val
{
    return '0' + val;
}

Code::Code()
    : myLength(0),
      myChars(MAXLEN)
{
    
}

Code::Code(const apstring & s)
    : myLength(s.length()),
      myChars(MAXLEN)
{
    int k;
    for(k=0; k < myLength; k++)
    {
	myChars[k] = s[k];
    }
}

bool Code::IsValid()
// postcondition: returns true if MINLEN <= Length() < MAXLEN - 2
//                and for every k, 0 <= k < Length(),
//                myChars[k] is a digit '0'--'9' or a char 'A' -- 'Z'
{

    if (Length() < MINLEN || MAXLEN - 2 < Length())
    {
	return false;
    }
    
    int k;
    for(k=0; k < Length(); k++)
    {
	if (! isupper(myChars[k]) && ! isdigit(myChars[k])) return false;
    }    
    return true;
}

void Code::AppendCheckSum()
// postcondition:  if IsValid() then myLength is updated and 
//                 myChars contains the original characters followed
//                 by a dash and the appropriate checksum; otherwise
//                 myLength and myChars are unchanged
{
    if (IsValid())
    {
	int k;
	int sum = 0;
	int len = Length();         // could use myLength here too

	for(k=0; k < len; k++)
	{
	    if (isdigit(myChars[k]))
	    {
		sum += digitToInt(myChars[k]);
	    }
	}
	myChars[myLength]   = '-';
	myChars[myLength+1] = intToDigit(sum % 10);
	myLength += 2;
    }
}


int Code::Length()
{
    return myLength;
}

void Code::print(ostream & os) const
{
    int k;
    for(k=0; k < myLength; k++)
    {
	os << myChars[k];
    }
}


void doCode(Code c)
{
    cout << c;
    if (c.IsValid())
    {
	c.AppendCheckSum();	
	cout << " is valid with check sum = " << c << endl;
    }
    else
    {
	cout << " is NOT valid" << endl;
    }
    
}

int main()
{
    Code a("ABCDE9999");
    Code b("ab?XX123");

    doCode(a);
    doCode(b);
    
}