help with if else if statement and characters

i haven't programmed in c++ in probably two years.
i was just bored and trying to make a simple program for myself.
here is the code i am having some trouble with.
i know it's probably smething simple, but i just cant figure it out
and i don't have any books in front of me to look at.

Code:

cout << "Did someone else work with you? (y/n)";
    cin >> a;
    {
		if (a = 'y' || 'Y')
		{
			cout << "Enter how many days they helped you: ";
			cin >> days;
			help = ((d / 2) * days);
			cout << "Your helper should be paid: $";
			cout << help;
			cout << "                                                                                ";	
		}
		else if (a = 'n' || 'N')
		{
			return 0;
		}
	}

basically i can't get it to tell whether you enter a y or n.
everythng i want to run for entering y runs no matter what
character you enter. help me please...

> if (a = 'y' || 'Y')

if (a == 'y' || a == 'Y')

Remember, = is assignment, == is comparison.

thanks