Operators and expressions

Arithmetic operators

Java provides several arithmetic operators that let you perform mathematical calculations.

Symbol	Name	Description
+	Addition	Adds two values
-	Subtraction	Finds the difference between two values
*	Multiplication	Multiplies two values
/	Division	Divides one value by another
%	Remainder	Calculates the remainder on division

Expressions

An expression in Java is a collection of operators and variables that evaluates to a single value.

java

public class Main {
    public static void main(String[] args) {
        int bookPrice = 15; // variable
        int numberOfBooks = 100; // variable
        int totalValue = bookPrice * numberOfBooks; // expression

        System.out.println(totalValue);
    }
}

output

1500

INFO

int in Java is an integer, whereas double is used for decimal numbers.

Exponentiation

There is no exponentiation operator in Java. Instead, you use Math.pow.

java

public class Main {
  public static void main(String[] args) {
    double result = Math.pow(2, 3);
    System.out.println(result);
  }
}

output

8.0

Modifying a Variable

When updating a variable, we can use its old value to calculate its new value.

java

public class Main {
    public static void main(String[] args) {
        int availableBooks = 120;
        availableBooks = availableBooks + 10;

        System.out.println(availableBooks);
    }
}

output

130

We can do this a bit more quickly with += and -=.

java

public class Main {
    public static void main(String[] args) {
        int availableBooks = 120;

        availableBooks += 10;
        System.out.println(availableBooks);

        availableBooks -= 5;
        System.out.println(availableBooks);
    }
}

output

130
125