first java am stuck

[yoga nina]

I have wasted all weekend trying to sort this out. If anyone can help i'd so appreciate it.
This is suppossed to be a leap year calculator. The values of the variables were given.
I thought I had worked it out all right but my if (and, or) staement keeps getting a error " bad operand types for binary operator ||"
I promise to read the FAQs when I have more time,
Cheers

public class Calculator {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {

        int year, R1, R2, R3, R4;
        year = 1998;   //enter year here//
        R1 = (year % 4);  //calculates remainders//
        R2 = (year % 100);
        R3 = (year % 400);
        R4 = (4 -R1);    // years until leap year

        if (R1 == 0 && (R2 !== 0 || R3 = 0));
             {System.out.println("This is a leap year");
             }
        }
}

[Suhas Mandrawadkar]

if (R1 == 0 && (R2 !== 0 || R3 = 0));  //should be R3 ==0
{System.out.println("This is a leap year"); 
} 

R3 = 0 does not evaluate to a boolean. It is just an assignment.
'=' - assignment operator
'==' - equality operator.

Read more on operators - Equality, Assignment and Logical

[Kurt Van Etten]

Hi,

In your program line:

if (R1 == 0 && (R2 !== 0 || R3 = 0));

you've got one too few "=" in your R3 comparison, so it is actually an assignment. This is a fairly common newbie error. One nice thing about Java is that it will catch this kind of error at compile time. In a language like C or C++, the assignment R3 = 0 will be treated logically as false no matter what value R3 had going into the expression. (It looks like you may have some other syntax errors in your code as well, but one at a time!)

By the way, one of the things the FAQ may mention is that you should surround your program excerpts in code brackets (you can use the button at the top of the message editor). That will display your code with formatting for easier reading.

[yoga nina]

still stuck
Thanks guys but the missing = was just a silly typo on my part.
The message still comes up "illegal start of expression, bad operand types for binary operator ||, first type int, second type boolean"
I just don't get this as all my varaibles are int, the operators are boolean, but yeah so?
cheers, guys
will read FAQ in morning

[Suhas Mandrawadkar]

You also have an extra "=" in "!==" and a semi colon at the end of line. It should be

if (R1 == 0 && (R2 != 0 || R3 = 0))  

Sorry, my bad. I could not point it out earlier

[yoga nina]

Thanks Suha, you're a star.
All done, can get some rest now.
Bless you

[Suhas Mandrawadkar]

Glad, I could be of your help.
But please do read more on operators - Equality, Assignment and Logical. You got all of them wrong together in a single Line of Code.

[Campbell Ritchie]

Welcome to the Ranch

Confusing == and = is a very common mistake.

[Angus Comber]

I hope this example might be useful.

import java.io.*;

public class Calculator {  
   public static void main(String[] args) {  
      BufferedReader br = null;
      int year, R1, R2, R3, R4;  
      try {
	br = new BufferedReader(new InputStreamReader(System.in));
	System.out.print("Enter a year: ");
	String value = br.readLine();
	year = Integer.parseInt(value);

        R1 = (year % 4);  //usually being divisible by 4 means a leap year
        R2 = (year % 100);  //Years that are evenly divisible by 100 are not leap years
        R3 = (year % 400);  //unless they are also evenly divisible by 400, in which case they are leap years
  
        if (R1 == 0 && (R2 != 0 || R3 == 0))  {
           System.out.println("This is a leap year");  
        } else {
           System.out.println("This is not a leap year"); 
        }
      } catch(Exception ex) {
         ex.printStackTrace();
      }
    } 
}