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Java Numbers

Java numbers are the numeric values a program counts and measures with. Whole numbers use int or long, and decimal numbers use float or double.

Whole numbers

The int variable holds a small count. The long variable holds a large distance.

public class Main {
  public static void main(String[] args) {
    int count = 25;
    long distance = 9000000000L;
    System.out.println(count);
    System.out.println(distance);
  }
}

Decimal numbers

The float variable carries the letter f. The double variable holds a price with two decimal places.

public class Main {
  public static void main(String[] args) {
    float temperature = 36.5f;
    double price = 19.99;
    System.out.println(temperature);
    System.out.println(price);
  }
}

Scientific notation

The first value uses e3 and prints as 3500.0. The second value uses e-2 and prints as 0.025.

public class Main {
  public static void main(String[] args) {
    double big = 3.5e3;
    double small = 2.5e-2;
    System.out.println(big);
    System.out.println(small);
  }
}

Example

public class Main {
  public static void main(String[] args) {
    int items = 120;
    long totalItems = 4500000000L;
    double length = 2.5e2;
    System.out.println(items);
    System.out.println(totalItems);
    System.out.println(length);
  }
}

Key points

  • int holds whole numbers in the range most programs need.
  • long holds larger whole numbers and its values carry the letter L.
  • double holds decimal numbers with more precision.
  • float holds decimal numbers and its values carry the letter f.
  • Scientific notation writes a number with the letter e.
  • In 3.5e3, the e3 part moves the decimal point three places.

In this example, an int holds a count of 120 and a long holds a much larger count. The length variable uses scientific notation with e2. The value 2.5e2 prints as 250.0.

Note

A decimal value with no letter is a double by default.

Try it Yourself

Edit the code, then press Run.

Running is simulated · Programiz Java Compiler

Exercise

What does the value 3.5e3 print as?