用函数简化 if 语句

Question

I am working on a calendar project for a school seminar. It is supposed to print three months that go after each other. (You specify you want it to print January and it prints December of previous year, January and February).

I have this if statement for this, but I would like to simplify it into three lines of code. How do I do it? Is it possible?

if (month == 1) {
    printMonth(12, year-1);
    printMonth(month, year);
    printMonth(month+1, year);
} else if (month == 12) {
    printMonth(month-1, year);
    printMonth(month, year);
    printMonth(1, year+1);
} else {
    printMonth(month-1, year);
    printMonth(month, year);
    printMonth(month+1, year);
}

Answer 1

Try using ternary operator :

printMonth(month == 1 ? 12 : month - 1, month == 1 ? year - 1 : year);
printMonth(month, year);
printMonth(month == 12 ? 1 : month + 1, month == 12 ? year + 1 : year);

Answer 2

You could use the Joda DateTime class to represent the current year/month, which is probably better than carrying years and month around as independent integers.

Then you could write:

printMonth(dt.minusMonths(1));
printMonth(dt);
printMonth(dt.plusMonths(1));

Answer 3

When I had such a problem myself, I tended to use an approach of combining year and month (also because I wanted to save some lines of code):

int monthAndYear = year * 12 + month;

printMonth(monthAndYear - 1);
printMonth(monthAndYear);
printMonth(monthAndYear + 1);

As you can see, this requires you to adjust the printMonth method, if it is possible of course.

private void printMonth(int monthAndYear) {
    int year = monthAndYear / 12;
    int month = monthAndYear % 12;
    // other code...
}

And these are still four lines though...