Year,Month,Day...? Anyone?

[ProgrammingIgnorant]

How's it going guys, I need a little help on this code I am working on for the extra credit problem on my homework. It says to write a C++ program to allow users to enter an integer y (year)from the key board, calculate n and p by using the following algorithms, and display n as month and p+1 as day on the screen. I am not sure I understand what the program is supposed to do. When I read it, it sounds like it wants you to type in a year and then its supposed to bring up a month and a day? That does not make too much sense to me seeing as there is 12 months in a year and 30+ days in any month. I do not see how typing in a year will select one month and day. The instructions then say

Divide y by 19 and call the remainder a. Ignore the quotient.
Divide y by 100 and get the quotient b and a remainder c.
Divide b by 4 and get a quotient d and a remainder e.
Divide b + 8 by 25 and get a quotient f. Ignore the remainder.
Divide b-f+1 by 3 and get a quotient g. Ignore the remainder.
Divide 19 * a + b - d - g + 15 by 30 and get remainder h. Ignore the quotient.
Divide c by 4 and get quotient I and remainder k.
Divide 32 + 2 * e + 2 * i - h - k by 7 and get a remainder r. Ignore quotient.
Divide a + 11 * h + 22 * r by 451 and get a quotient m. Ignore the remainder
Divide h + r - 7 * m + 114 by 31 and get a quotient n and a remainder p.

The code I compiled was

  #include <iostream>
#include <math.h>

using namespace std;

int main ()
{
	int year;

	cout << "Please Enter a Year" << " \n " ;
	cin >> year;

	int a=(year/19);
	int b=(year%100);
	int c= (year/100);
	int d= (b%4);
	int e= (b/4);
	int f= (b+8%25);
	int g= (b-f+1%3);
	int h= (19*a+b-d-g+15/30);
	int i= (c%4);
	int k= (c/4);
	int r = (32+2*e+2*i-h-k/7);
	int m = (a+11*h+22*r%451);
	int n= (h+r-7*m+114%31);
	int p= (h+r-7*m+114/31);

	

	cout << " Month is " << n << " \n ";
	cout << " Day is " << p+1 << " \n"; 


	system ("pause");
	return 0;
}

When I run the code I receive negative numbers. I am lost on what I am supposed to receive and this is also only the second time I have used a compiler for the second homework. Sorry if this is really simple. I have never looked into or played with a programing compiler before this course.

[dhayden]

You have your quotients and remainders wrong. Line 13 computes the quotient, not the remainder. Line 14 computes the remainder, not the quotient.

x/y gives the quotient. x%y gives the remainder.

I think the program computes the month/day of Easter.

[ProgrammingIgnorant]

Okay sorry about that, I switched all my incorrect signs and ended up with this

#include <iostream>
#include <math.h>

using namespace std;

int main ()
{
	int year;

	cout << "Please Enter a Year" << " \n " ;
	cin >> year;

	int a=(year%19);
	int b=(year/100);
	int c= (year%100);
	int d= (b/4);
	int e= (b%4);
	int f= (b+8/25);
	int g= (b-f+1/3);
	int h= (19*a+b-d-g+15%30);
	int i= (c/4);
	int k= (c%4);
	int r = (32+2*e+2*i-h-k%7);
	int m = (a+11*h+22*r/451);
	int n= (h+r-7*m+114/31);
	int p= (h+r-7*m+114%31);

	

	cout << " Month is " << n << " \n ";
	cout << " Day is " << p+1 << " \n"; 


	system ("pause");
	return 0;
}

However when I run the program I still get just negative numbers. Im not understanding what the program is supposed to give me back. For example when I run it and input the year 2002 in return I get the number -12525 for the month and -12506 for the day. What is the program supposed to give me?

[dhayden]

On line 18, the compiler interprets b+8/25 as b+(8/25), not (b+8)/25. Multiplication/division have higher precedence than addition/subtraction. You have the same problem is several other places.

The program will print out the month and day number of Easter for the year that you give it.

[ProgrammingIgnorant]

Alright thank you for the help I finally got the code working correctly. The code is for a Anonymous Gregorian algorithm to find the month and day of Easter for the year that you input. I was missing the parentheses in all of my lines which caused the system to bug out. To get the remainder you use the percent sign % to get the quotient you use the division sign /. I had it correct on the first code I was using but the lack of parentheses was messing up the code. I added parentheses and switched back all the signs and ended up with a working code.

#include <iostream>
#include <math.h>
using namespace std; 

int main ()
{
	int year;

	cout << "Please enter the year you want the date of Easter for " << " \n " ;
	cin >> year;

	int a=(year%19);
	int b=(year/100);
	int c= (year%100);
	int d= (b/4);
	int e= (b%4);
	int f= ((b+8)/(25));
	int g= ((b-f+1)/(3));
	int h= ((19*a+b-d-g+15)%(30));
	int i= (c/4);
	int k= (c%4);
	int r = ((32+2*e+2*i-h-k)%(7));
	int m = ((a+11*h+22*r)/(451));
	int n= ((h+r-7*m+114)/(31));
	int p= ((h+r-7*m+114)%(31));

	cout << " The number of the month easter is/was on is " << n << " \n ";
	cout << " The number of the day easter is/was on is " << p+1 << " \n"; 


	system ("pause");
	return 0;
}

Thank you so much for the help and I hope to learn plenty more off of this site.