// Input: Two Dates 
// Output: # of days between the two dates 
#include <iostream.h>

int DaysInMonth(int, int); 
int LeapYear(int); 
int DaysInYear(int); 

main() { 
	int Day1, Month1, Year1; 
	int Day2, Month2, Year2; 
	int DaysElapsed; 

	// 1. Input the two dates 
	cout << "Enter the day1:"; cin >> Day1; 
	cout << "Enter month1:"; cin >> Month1; 
	cout << "Enter Year1:"; cin >> Year1; 
	cout << "Enter the day2:"; cin >> Day2; 
	cout << "Enter month2:"; cin >> Month2; 
	cout << "Enter Year2:"; cin >> Year2; 

	// 2. Initialize DaysElapsed to 0 DaysElapsed = 0; 
	// Compute the # of days elapsed 
	// If the two dates are in a different year 
	if (Year2 > Year1) { 
		// Add all the days from Day1 to Dec 31 or Year1 
		// Add all the remaining days in Month1 
		DaysElapsed += DaysInMonth(Month1, Year1) - Day1; 

		// Add all the days in remaining months until Dec 
		for (int m=Month1+1; m <= 12; m++) 
			DaysElapsed += DaysInMonth(m, Year1); 

		// Add all the days in each year between Year1 and Year2 
		for (int y=Year1+1; y < Year2; y++) 
			DaysElapsed += DaysInYear(y); 

		// Add all the days from Jan1 of Year2 until Day2 
		// Add all the days in months from Jan until previous month 
		for (int m=1; m < Month2; m++) 
			DaysElapsed += DaysInMonth(m, Year2); 

		// Add Day2 
		DaysElapsed += Day2; 
	} 
		
		// 3. Output the two dates and days elapsed 
		cout << "Date 1: " << Month1 << "/" << Day1 << "/" << Year1 << endl; 
		cout << "Date 2: " << Month2 << "/" << Day2 << "/" << Year2 << endl; 
		cout << "# of days between the two dates is " << DaysElapsed << endl; 
} 

int DaysInYear(int y) { 
	if (LeapYear(y)) 
		return 366; 
	else 
		return 365; 
} 

int LeapYear(int y) { 
// determines if y is a leap year 
	return ((((y % 4) == 0) && ((y % 100) != 0)) || ((y % 400) == 0)); 
}
 
int DaysInMonth(int m, int y) {
 // Computes the number of days in month m in year y 
	switch (m) { 
	case 1: 
	case 3: 
	case 5: 
	case 7: 
	case 8: 
	case 10: 
	case 12: return 31; 
	case 4: 
	case 6: 
	case 9: 
	case 11: return 30; 
	case 2: if (LeapYear(y)) 
				return 29; 
			else 
				return 28; 
	} 
	return 0; 
}