Using If-Else-If statement but it keeps saying it is an invalid entry

[bryantbe]

System.out.println("Enter the day of the month. ");
  dayOfMonth = keyboard.nextInt();
 
   System.out.println("Enter the month. ");
  monthName = keyboard.nextLine();
 
   System.out.println("Enter the year. ");
  int Year = keyboard.nextInt();
 
  if (Year/4){
  if (Year/ 4 && Year/100)
   {isItLeapYear=true;}
  else if (Year/4 && Year/100 && Year/400)
   {isItLeapYear=true;}
 } else {isItLeapYear=false;}

it says that I cannot use Year/ because it is an int not Boolean..

[bryantbe]

This is what is says NumDaysLeftInYear.java:61: error: incompatible types
if (Year/4){
^
required: boolean
found: int
NumDaysLeftInYear.java:62: error: bad operand types for binary operator '&&'
if (Year/ 4 && Year/100)
^
first type: int
second type: int

[Rabbit]

Please use code tags when posting code or formatted data.

The binary operator && compares two booleans. A boolean is either true or false. Year / 4 and Year / 100 is not a true or false statement. A comparison of the result to an expected value is a true or false statement but just the result itself is neither true or false. It's like asking if 1 + 1 is true or false. It is not a true or false question. But asking if 1 + 1 is equal to 2 is a true or false question.

Also, you should know that you don't need to check Year / 4 twice. There's no point in doing so.

[rajujrk]

Hi,

Please go over Java Basics.

if statement allows only boolean type

if(<boolean_value>){
        -----
}{
        -----
}
 

Year is int, then Year/4 will return int or double type

these types are not allowed inside the if statement

Thanks
Raju

[Nepomuk]

What you probably wanted is something like this:

if (Year % 4 == 0){
  if (Year % 4 == 0 && Year % 100 == 0)
    {isItLeapYear=true;}
  else if (Year % 4 == 0 && Year % 100 == 0 && Year % 400 == 0)
   {isItLeapYear=true;}
 } else {isItLeapYear=false;}

The Modulo-operator (%) will calculate what number is left when dividing the first number by the second one; so for example 9 % 4 == 1 as there is a number x for which x * 4 + 1 == 9.

Mind you, the else if-case will never be reached as all years that fulfil the condition is divisible by 4, 100 and 400 also fulfil the condition is divisible by 4 and 100 (which is the condition in the if-condition before the else if).