Roman Numeral Calculator

Beginning stages of a roman numeral to regular number calculator. This program assumes that the user is going to enter a valid roman numeral. Compiles fine, but numbers are always 1000 for some reason. Need a second pair of eyes on this:

Code:

#include<iostream>
#include<cstdlib>
#include<string>
#include<iomanip>
#include<conio.h>

#define I 1
#define V 5
#define X 10
#define L 50
#define C 100
#define D 500
#define M 1000

using namespace std;

class Roman
{
public:
	//Function Prototypes
	Roman(){total=0; counter=0;}
	void menu(void);
	bool is_ronumeral(const char&) const;
	void calculate(char&);
	void error_message(void);

private:
	//Globals
	int total;
	int counter;
	string user_input;
	int numarray[80];
};

int main()
{
	Roman numeral;

	char choice;	

	do{
		system("cls");
		
		numeral.menu();

		choice=toupper(getch());		

		if(numeral.is_ronumeral(choice)  && choice!='Q')

			numeral.calculate(choice);
		
		if(!numeral.is_ronumeral(choice) && choice!='Q')

			numeral.error_message();

	}while(choice!='Q');

	system("cls");

	return EXIT_SUCCESS;
}

void Roman::menu(void)
{
	cout << endl << endl
		 << setw(10) << "***************************************"     << endl
		 << setw(10) << "* Welcome to Roman Numeral Calcultor! *"     << endl
		 << setw(10) << "***************************************\n"   << endl
		 << setw(10) << "Enter your roman numerals one at a time"     << endl
		 << setw(10) << "Enter 'Q' to Quit\n\n"
		 << endl << endl
		 << "\tNumerals Entered: " << user_input 
		 << "\n\n\tCurrent Total: " << total
		 << endl << endl << endl << endl << endl 
		 << "\tEnter Roman Numeral: ";
}

bool Roman::is_ronumeral(const char& keydown) const
{
	switch(keydown)
	{
		case 'I':
		case 'V':
		case 'X':
		case 'L':
		case 'C':
		case 'D':
		case 'M': return true;		 

		default:  return false;
	}
}

void Roman::calculate(char& numeral) 
{
	user_input+=numeral;
	user_input+=" ";

	switch(numeral)
	{
		case 'I': numarray[counter]=I;
		case 'V': numarray[counter]=V;
		case 'X': numarray[counter]=X;
		case 'L': numarray[counter]=L;
		case 'C': numarray[counter]=C;
		case 'D': numarray[counter]=D;
		case 'M': numarray[counter]=M;
	}

	if(!counter)
		total=numarray[counter];	

	else
	{
		if(numarray[counter]<=numarray[counter-1])
			total += numarray[counter];

		if(numarray[counter]>numarray[counter-1])
			total += (numarray[counter] - numarray[counter-1]);
	}

	++counter;
}

void Roman::error_message(void)
{
	cout << "\n\n\t\aThat is not a Roman Numeral!  Try Again.";	
	cout << "\n\b\tPress [Enter] to continue...";
	//cin.ignore(200,'n');
	cin.get();
}

I think you forgot breaks on the case statement

EDIT
Yep, that was the problem

good call

Code:

void Roman::calculate(char& numeral) 
{
	user_input+=numeral;
	user_input+=" ";

	switch(numeral)
	{
		case 'I': numarray[counter]=I;
			  break;
		case 'V': numarray[counter]=V;
			  break;
		case 'X': numarray[counter]=X;
			  break;
		case 'L': numarray[counter]=L;
			  break;
		case 'C': numarray[counter]=C;
			  break;
		case 'D': numarray[counter]=D;
			  break;
		case 'M': numarray[counter]=M;
                          break;			     
	}

Think I got the final program here:

Code:

#include<iostream>
#include<cstdlib>
#include<string>
#include<iomanip>
#include<conio.h>

#define I 1
#define V 5
#define X 10
#define L 50
#define C 100
#define D 500
#define M 1000

using namespace std;

class Roman
{
public:
	//Function Prototypes
	Roman(){total=0; counter=0;}
	void menu(void);
	bool is_ronumeral(const char&) const;
	void calculate(char&);
	void error_message(void);

private:
	//Globals
	int total;
	int counter;
	string user_input;
	int numarray[80];
};

int main()
{
	Roman numeral;

	char choice;	

	do{
		system("cls");
		
		numeral.menu();

		choice=toupper(getch());		

		if(numeral.is_ronumeral(choice)  && choice!='Q')

			numeral.calculate(choice);
		
		if(!numeral.is_ronumeral(choice) && choice!='Q')

			numeral.error_message();

	}while(choice!='Q');

	system("cls");

	return EXIT_SUCCESS;
}

void Roman::menu(void)
{
	cout << endl << endl
		 << setw(10) << "***************************************"     << endl
		 << setw(10) << "* Welcome to Roman Numeral Calcultor! *"     << endl
		 << setw(10) << "***************************************\n"   << endl
		 << setw(10) << "Enter your roman numerals one at a time"     << endl
		 << setw(10) << "Enter 'Q' to Quit\n\n"
		 << endl << endl
		 << "\tNumerals Entered: " << user_input 
		 << "\n\n\tCurrent Total: " << total
		 << endl << endl << endl << endl << endl 
		 << "\tEnter Roman Numeral: ";
}

bool Roman::is_ronumeral(const char& keydown) const
{
	switch(keydown)
	{
		case 'I':
		case 'V':
		case 'X':
		case 'L':
		case 'C':
		case 'D':
		case 'M': return true;		 

		default : return false;
	}
}

void Roman::calculate(char& numeral) 
{
	user_input+=numeral;
	
	switch(numeral)
	{
		case 'I': numarray[counter]=I;
			      break;
		case 'V': numarray[counter]=V;
			      break;
		case 'X': numarray[counter]=X;
			      break;
		case 'L': numarray[counter]=L;
			      break;
		case 'C': numarray[counter]=C;
			      break;
		case 'D': numarray[counter]=D;
			      break;
		case 'M': numarray[counter]=M;			     
	}

	if(!counter)
		total=numarray[counter];	

	else
	{
		if(numarray[counter]<=numarray[counter-1])
			total += numarray[counter];

		if(numarray[counter]>numarray[counter-1])
			total += (numarray[counter] - (2 * numarray[counter-1]));
	}

	++counter;
}

void Roman::error_message(void)
{
	cout << "\n\n\t\aThat is not a Roman Numeral!  Try Again.";	
	cout << "\n\tPress [Enter] to continue...";
	cin.get();
}