Java Operators

Operators are symbols that do work on values, like adding numbers or comparing them.

Arithmetic Operators

Operator	Name	Example	Result
`+`	Addition	`7 + 3`	`10`
`-`	Subtraction	`7 - 3`	`4`
`*`	Multiplication	`7 * 3`	`21`
`/`	Division	`7 / 3`	`2`
`%`	Remainder (modulus)	`7 % 3`	`1`
`++`	Increment	`x++`	adds 1
`--`	Decrement	`x--`	subtracts 1

Example

java

public class Main {
  public static void main(String[] args) {
    int total = 1250;
    int people = 4;

    System.out.println(total / people);
    System.out.println(total % people);
    System.out.println(total / 4.0);
  }
}

Output

312
2
312.5

When both numbers are int, Java does integer division and drops the decimal part. Make one of them a double (like 4.0) to get the exact answer.

Assignment Operators

Operator	Same as
`x = 5`	put 5 in x
`x += 3`	`x = x + 3`
`x -= 3`	`x = x - 3`
`x *= 3`	`x = x * 3`
`x /= 3`	`x = x / 3`

Example

java

public class Main {
  public static void main(String[] args) {
    int balance = 1000;
    balance += 500;   // salary arrives
    balance -= 200;   // mobile load
    balance++;        // one rupee bonus
    System.out.println(balance);
  }
}

Output

Comparison Operators

Comparison operators give a boolean answer: true or false.

Operator	Meaning
`==`	equal to
`!=`	not equal to
`>`	greater than
`<`	less than
`>=`	greater than or equal to
`<=`	less than or equal to

Logical Operators

Logical operators combine conditions:

&& (and): true only if both sides are true
|| (or): true if at least one side is true
! (not): flips true to false and false to true

Example

java

public class Main {
  public static void main(String[] args) {
    int age = 20;
    boolean hasCnic = true;

    System.out.println(age >= 18);
    System.out.println(age >= 18 && hasCnic);
    System.out.println(age < 18 || !hasCnic);
  }
}

Output

true
true
false

Order of Operations

Java follows normal maths rules: *, / and % happen before + and -. Use brackets to make the order clear:

Example

java

int a = 2 + 3 * 4;     // 14
int b = (2 + 3) * 4;   // 20

Exercise

What is the value of 17 % 5 in Java?

323.412