Java double type creation and comparison

In this chapter you will learn:

How to find max and min values for double type
How to create double class with constructor
How to find out if a double value is an infinite large value, or it is not a number

double type max/min values

Double class defines the following constants to stores its min, max value and its size.

static int MAX_EXPONENT stores maximum exponent a finite double variable may have.
static double MAX_VALUE stores largest positive finite value of type double.
static int MIN_EXPONENT stores minimum exponent a normalized double variable may have.
static double MIN_NORMAL stores smallest positive normal value of type double.
static double MIN_VALUE stores smallest positive nonzero value of type double.
static double NaN stores Not-a-Number (NaN) value of type double.
static double NEGATIVE_INFINITY stores negative infinity of type double.
static double POSITIVE_INFINITY stores positive infinity of type double.
static int SIZE stores the number of bits used to represent a double value.

The following code finds out the min/max value a double type variable can have. It also prints out the size of a double value.

public class Main {
  public static void main(String[] args) {
    System.out.println(Double.MAX_VALUE);
    System.out.println(Double.MIN_VALUE);
    System.out.println(Double.SIZE);// java 2  s .  c  o  m

  }
}

The output:

public class Main {
  public static void main(String[] args) {
    System.out.println(Double.MAX_EXPONENT);
    System.out.println(Double.MIN_EXPONENT);
    System.out.println(Double.MIN_NORMAL);
/*from   java2s . c o m*/
  }
}

The output:

The following code uses the Double.NEGATIVE_INFINITY to check a double value.

public class Main {
  public static void main(String args[]) {
//from ja  v a  2s  .c o  m
    double d = -10.0 / 0.0;
    if (d == Double.NEGATIVE_INFINITY) {
      System.out.println("d = " + d);
    }

  }
}

The output:

Create Double class with Constructor

We can create a double type object with the following two constructors.

Double(double value) creates a Double object that represents the primitive double argument.
Double(String s) creates a Double object that represents the double value represented by the string.

The following code creates two Double type object and one is from double primitive type and another is from a string value.

public class Main {
  public static void main(String[] args) {
    System.out.println(new Double(1.1));
    System.out.println(new Double("1.2"));
//from ja  va 2  s. c  om
  }
}

The output:

Is a double value an infinite large value, or it is not a number

isInfinite() returns true if the value being tested is infinitely large or small in magnitude. isNaN() returns true if the value being tested is not a number.

boolean isInfinite() returns true if this Double value is infinitely large in magnitude, false otherwise.
static boolean isInfinite(double v) returns true if the specified number is infinitely large in magnitude, false otherwise.
boolean isNaN() returns true if this Double value is a Not-a-Number (NaN), false otherwise.
static boolean isNaN(double v) returns true if the specified number is a Not-a-Number (NaN) value, false otherwise.

The following code divides 1 by 0 and creates a infinite double value and then its uses the isInfinite() to check.

public class Main {
  public static void main(String[] args) {
    Double double1 = new Double(1/0.0);
    //from ja  v  a 2 s  .com

    System.out.println(double1.isInfinite());

  }
}

The output:

public class Main {
  public static void main(String[] args) {
    Double double1 = new Double(0.0/0.0);
    /*from   jav a  2  s  .  com*/
    System.out.println(Double.isNaN(double1));
    System.out.println(double1.isNaN());

  }
}

The output:

Java double type creation and comparison

double type max/min values

Create Double class with Constructor

Is a double value an infinite large value, or it is not a number

Next chapter...

Introduction

Boolean

Char

Byte

Short

Integer

Long

Float

Double

Java double type creation and comparison

Data Type Conversion