Prerequisite: Data Types in Java
In this article you will see the use of boolean data type in Java along with suitable examples.
Java boolean Data Type with Example
boolean:
boolean
keyword which is a primitive data type. It stores two possible values i.e true
or false
. This is considered as the basis for many conditions or comparisons. The default value of boolean variable is false
.
All relational operators returns this boolean value. It is also used in case of conditional statements or loops.
boolean
can be used with variables or methods.
Synatx to declare boolean variable:
boolean varName = true/false;
Where,
varName
refers to name of the variable.true/false
refers to the value of variable i.e. either true or false.
Syntax to declare boolean method:
boolean methodName() { //method body }
Where,
boolean
refers to the type of method.methodName
refers to name of the method.
Let’s see some example programs to understand it more clearly.
- Declare boolean variables with true/false value and Print it
- boolean value result with conditional operators
- Declare boolean type method
Example-1: Declare boolean variables with true/false value and Print it
Approach:
- Here we have taken two boolean variables say
varOne
andvarTwo
and initialized it withtrue
andfalse
value respectively. - Then printing the values of those variables.
Program:
class Main { public static void main(String[] args) { boolean varOne = true ; boolean VarTwo = false; System.out.println(varOne); System.out.println(VarTwo); } }
Output: true false
Example-2: boolean value result with conditional operators
Approach:
- Here we have declared an boolean expression by using conditional operators.
- And printing the output as true or false.
Program:
import java.util.*; class Main { public static void main(String[] args) { //declared two integer variables i.e. number1 and number2 //inituialized values of both variables int number1 = 50; int number2 =21; //comparing two values using comparision operator // as result it returns true or false value System.out.println(number1 < number2); // checking is number1 is less than number2 System.out.println(number1 > number2); // checking is number1 is greater than number2 System.out.println(number1 == number2); // checking are both number1 and number2 equal } }
Output: false true false
Example-3: Declare boolean type method
Approach:
- Here we have taken a user defined method of type
boolean
means return type isboolean
so it will returntrue
orfalse
value as result.
Program:
import java.util.*; class Main { public static void main(String[] args) { //object of Scanner class is created Scanner sc=new Scanner(System.in); System.out.print("Enter a number: "); int number = sc.nextInt(); //calling a user defined method say checkNumber() and passing 'number' as parameter //declared boolean type variable say result to store the result of checkNumber() method boolean result=checkNumber(number); System.out.print("is entered number greater than 50? "+result); } //checkNumber() method to check numbner is greater than 50 or not //return type of method is boolean public static boolean checkNumber(int number) { //if number is greater than 50 then return true if(number>50) return true; //else return false else return false; } }
Output: Case-1 Enter a number: 68 is entered number greater than 50? true Case-2 Enter a number: 7 is entered number greater than 50? false