Help in project!

[Shiv4life]

Ok...i am doing a school project...basically you input a year and it will tell you what date easter falls on in that year. Believe it or not...there is a mathematical way to find it out. Check this out:

#include <cstdlib>
#include <iostream>

using namespace std;

int main()
{
    int year, b, c, a, s, r, t, h, g, j, k, m, n, q, p;
    char month;
    cout<< "This program designed by Shiv (in C++) will find the date of Easter in the year you choose... \n";
    cout<< "Please choose the year: ";
    cin>> year;
    cin.ignore();
    b = year / 100;
    c = year % 100;
    a = (5*b + c) % 19;
    r = (3*b + 75) / 4;
    s = (3*b + 75) % 4;
    t = (8*b + 11) / 25;
    h = (19*a + r - t) % 30;
    g = (a + 11*h) / 319;
    j = (300 - 60*s + c) / 4;
    k = (300 - 60*s + c) % 4;
    m = (2*j - k - h + g) % 7;
    n = (h - g + m + 110) / 30;
    q = (h - g + m + 110) % 30;
    p = (q + 5 - n) % 32;
    if (n = 4) {
          char month = "April";
          }
    if (n = 3) {
          char month = "March";
          }
    cout<< "In year "<< year<<", Easter will be on Sunday "<< p<<" of "<< month;
    cin.get();
    
}

In the code...the interger n is either 3 or 4, if it is 3 the month is march, if it is 4 the month is april...so im trying to make if statements to do the recognising...but its not working:

if (n = 4) {
          char month = "April";
          }
    if (n = 3) {
          char month = "March";
          }

Any help to doing it would be greatly appreciated...thanks.

[treenef]

Try using strings instead?

#include <cstdlib>
#include <iostream>
#include <string>

using namespace std;

int main()
{
    int year, b, c, a, s, r, t, h, g, j, k, m, n, q, p;
    string month;
    cout<< "This program designed by Shiv (in C++) will find the date of Easter in the year you choose... \n";
    cout<< "Please choose the year: ";
    cin>> year;
    cin.ignore();
    b = year / 100;
    c = year % 100;
    a = (5*b + c) % 19;
    r = (3*b + 75) / 4;
    s = (3*b + 75) % 4;
    t = (8*b + 11) / 25;
    h = (19*a + r - t) % 30;
    g = (a + 11*h) / 319;
    j = (300 - 60*s + c) / 4;
    k = (300 - 60*s + c) % 4;
    m = (2*j - k - h + g) % 7;
    n = (h - g + m + 110) / 30;
    q = (h - g + m + 110) % 30;
    p = (q + 5 - n) % 32;
    if (n = 4) {
          month = "April";
          }
    if (n = 3) {
           month = "March";
          }
    cout<< "In year "<< year<<", Easter will be on Sunday "<< p<<" of "<< month;
    cin.get();
    
}

[Salem]

> if (n = 4)
It's ==, not =

Also, you need much better variable names than a,b,c,d,.....

[74466]

i am quite new at c++, just a few points,

if (n = 4) {
          month = "April";
          }
    if (n = 3) {
           month = "March";
          }

Should it not be like this

if (n = 4) {
          month = "April";
          }
    else if (n = 3) {
           month = "March";
          }

?

And another this, when i compile the code i get the following message in my compiler (i use borland 5.5)

warning w8060 possibly incorrect assignment in function main

At both the if lines.

Can anybody explain?

edit::: i found answer to 2nd question in previous reply

[Daved]

>> possibly incorrect assignment in function main

This is probably due to use of = instead of == as Salem pointed out.

The else if in this case is probably better, but either will work since n cannot == 4 and 3 at the same time.

[7stud]

Hi,

The problem you are experiencing trips up all beginning programmers. In C++ the equal sign is used to "assign" something a value, which means you are setting something equal to a value. For instance, this is an assignment using the equals sign:

int n = 4;

It results in n being set equal to 4.

Another thing you have to understand is that the condition in an if statement has to result in it either being true or false. So, let's see what happens when you write this:

if (n = 4)

First, n is assigned or set equal to the value 4. After that, the if statement conditional becomes:

if(n)

where n is 4. That means the if conditional becomes:

if(4)

Not only is that not what you intended the conditional to be, it doesn't even look like something that is true or false. However, all numbers except 0 are considered to be true, and 0 is considered to be false, so the if statement does not cause an error. Try running this program:

#include <iostream>
using namespace std;

int main()
{
	if(-1)
	{
		cout<<"-1 is true or else this wouldn't display."<<endl;
	}

	
	if(0)
	{
		cout<<"If this displays, 0 is true."<<endl;
	}
	else
	{
		cout<<"If this displays, 0 is false."<<endl;
	}

	
	if(1)
	{
		cout<<"1 is true or else this wouldn't display."<<endl;
	}



	return 0;
}

In C++, the double equals sign(==) is used to compare two things, and the mistake you are making is trying to use the single equals sign to compare things. You should not interpret this statement:

if(n=4)

to mean: "if n is equal to 4, then execute the following statments." You should interpret it to mean: "assign 4 to n, and then since 4 is always true, execute the following statements." Just remember that whenever you see "=" you should say "assign" to yourself--not "equal to". That way, this statement:

if(n=4)

would read: "if n assign 4" which doesn't make much sense, so you know it is an error.

However, when you see "==", you should interpret that to mean "equal to". That way if you write this:

if(n==4)

it will read: "if n is equal to 4", which is correct.