/* C++ Programming, Example answer, Exercise 3, Sheet 1  */

/* Author: Rob Miller and William Knottenbelt
   Program last changed: 28th September 2012    */

/* This program prompts the user for the current year and month, the user's 
current age in years and months, and another year and month. It then calculates 
the age that the user was or will be in the second year and month entered. */ 

#include <iostream>
using namespace std;
	
int main() 
{
	/* Variables for user input:   */
	int year_now, month_now, age_now, month_born, another_year, another_month; 
	/* Variables for program output: */
	int total_years, total_months;

	/* Variables for internal program use: */
	int age_now_in_months, extra_months_from_now;
		
	cout << "Enter the current year then press RETURN.\n";
	cin >> year_now;

	cout << "Enter the current month (a number from 1 to 12).\n";
	cin >> month_now;

	cout << "Enter your current age in years.\n";
	cin >> age_now;
						
	cout << "Enter the month in which you were born (a number from 1 to 12).\n";
	cin >> month_born;

	cout << "Enter the year for which you wish to know your age.\n";
	cin >> another_year;
								
	cout << "Enter the month in this year.\n";
	cin >> another_month;
	cout << "\n";
				
	/* Convert everything to months, then do the same calculation 
	as in Program 1.5.1 (some of the brackets in the following statements
	aren't strictly necessary): */
	
	age_now_in_months = (age_now * 12) + (month_now - month_born);
	if ((month_now - month_born) < 0)
		age_now_in_months = age_now_in_months + 12;
		
	extra_months_from_now = ((another_year * 12) + another_month) 
                                - ((year_now * 12) + month_now);
								
	total_months = age_now_in_months + extra_months_from_now;
	                     
	total_years = total_months / 12;

	if (total_months > (150 * 12)) { 
		cout << "Sorry, but you'll probably be dead by ";
		cout << another_month << "/" << another_year << "!\n";
	} else if (total_months >= 0) {
		cout << "Your age in " << another_month << "/" << another_year << ": ";
		cout << total_years << " year";
		if (total_years != 1)
			cout << "s";
		cout << " and " << total_months % 12 << " month";
		if ((total_months % 12) != 1)
			cout << "s";
		cout << ".\n";
	} else { 
		cout << "You weren't even born in ";
		cout << another_month << "/" << another_year << "!\n";
	}
							
	return 0;
}