C++

// Rom nums c++.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <iostream>
using namespace std;

char input[99];
//bool op = false;
int i = 0;
int num[99];
char op;



int inp(char input[],int num[], int i)
{
//Converts array values to numbers
	int tot = 0; //total
	for (i = 0; i <= 99; i++)
	{
		switch (input[i])
		{
		case 'm':
		case 'M':
			num[i] = 1000;
			break;
		case 'D':
		case 'd':
			num[i] = 500;
			break;
		case 'C':
		case 'c':
			num[i] = 100;
			break;
		case 'L':
		case 'l':
			num[i] = 50;
			break;
		case 'X':
		case 'x':
			num[i] = 10;
			break;
		case 'V':
		case 'v':
			num[i] = 5;
			break;
		case 'I':
		case 'i':
			num[i] = 1;
			break;
		case 0:
			num[i] = 0;
			break;
		default:
			cout << "You have not input a valid numeral. Please input a Roman numeral using the following numbers in descending order. Maximum value 4000."
				<< endl << "M = 1000 \n D = 500 \n C = 100 \n L = 50 \n X = 10 \n V = 5 \n I = 1\n";
			tot = -1; goto flop;
			break;

		}

	}
	//Code to output all input numerals and all the numbers they mean
	//for (i = 0; i <= 99; i++)
	//{
	//	cout << input[i] << " - " << num[i] << endl;
	//}

	//Checks for descending order
	for (i = 0; i <= 99; i++)
	{
		if (num[i] < num[i + 1])
		{
			cout << "The numeral must be input in descending order." << endl;
			tot = -1; goto flop;
		}
	}
	//checks for use of smaller numbers where a bigger number could be used
	int I = 0;
	int V = 0;
	int X = 0;
	int L = 0;
	int C = 0;
	int D = 0;
	int M = 0;
	for (i = 0; i <= 99; i++)
	{

		if (num[i] == 1)
		{
			I = I + 1;
		}
		if (num[i] == 5)
		{
			V = V + 1;
		}
		if (num[i] == 10)
		{
			X = X + 1;
		}
		if (num[i] == 50)
		{
			L = L + 1;
		}
		if (num[i] == 100)
		{
			C = C + 1;
		}
		if (num[i] == 500)
		{
			D = D + 1;
		}
		if (num[i] == 1000)
		{
			M = M + 1;
		}
	}
	if ((I >= 5) || (V >= 2) || (X >= 5) || (L >= 2) || (C >= 5) || (D >= 2))
	{
		cout << "You have input more numerals than needed - for example, 5 'I's - where it would be appropriate to use a 'V' instead" << endl;
		goto flop; tot = -1;
	}
	//adds all the numbers up


	for (i = 0; i <= 99; i++)
	{
		tot = tot + num[i];
	}

	cout << "Your number is: " << tot << endl;
	flop:
	return(tot);



	//Asks if the user wishes to restart the program
//	cout << "Input 'start' to restart, or anything else to quit";
//	char end[99];
//	cin >> end; cout << endl;
//	if (end == "start"){  goto start; }
//	return 0;
}




int main()
{
	//second input
	start:
	cout << "Please input your first number and press enter" << endl; //Prints a request for the input, and then starts a new line
	start2:
	cout << "Input: "; cin >> input; //Takes the input
	int num1 = inp(input, num, 0);
	if (num1 == -1) {goto start;}

	//first input
	cout << "Please input your second number and press enter" << endl; //Prints a request for the input, and then starts a new line
	cout << "Input: "; cin >> input; //Takes the input
	int num2 = inp(input, num, 0);
	if (num2 == -1) {goto start;}

	oper:
	cout << "Would you like to add or subtract?" << endl << "Input 'a' to add or 's' to subtract'" << endl;
	cin >> op;
	int total = 0;
	switch (op)
	{
		case 'a':
		case 'A':
			total = num1 + num2;
			break;
		case 's':
		case 'S':
			total = num1 - num2;
			if (total <= 0) {cout <<"The answer cannot be zero or negative." << endl << "The second number is subtracted from the first."; goto start;}
			break;

	}
	cout << "The answer is " << total;
	char out[20];
	for (i = 0; total<=0; i++)
	{
		if(total>=1000) {total = total-1000; out[i] = 'M';}
		else if(total>=500) {total = total-500; out[i] = 'D';}
		else if(total>=100) {total = total-100; out[i] = 'C';}
		else if(total>=50) {total = total-50; out[i] = 'L';}
		else if(total>=10) {total = total-10; out[i] = 'X';}
		else if(total>=5) {total = total-5; out[i] = 'V';}
		else if(total>=1) {total = total-1; out[i] = 'I';}
		else {out[i] = ' ';}

	}
	cout << " or ";
	for(i = 1; i <=20, i++)
	{cout << out[i];}
	cout endl;
	goto start;
}




int _tmain(int argc, _TCHAR* argv[])
{
	return 0;
}