Java Double Keyword

by Online Tutorials Library July 22, 2022

Java double keyword

The Java double keyword is a primitive data type. It is a double-precision 64-bit IEEE 754 floating point. It is used to declare the variables and methods. It generally represents the decimal numbers.

Points to remember

The double covers a range from 4.94065645841246544e-324d to 1.79769313486231570e+308d (positive or negative).
Its default value is 0.0d.
Its default size is 8 byte.
It is the default type for decimal numbers.
It is not a good approach to use double for precise values, such as currency.

Examples of Java double keyword

Example 1

Let’s see a simple example to display double type variable.

  public class DoubleExample1 {    public static void main(String[] args) {    double num=5.5;  System.out.println(“num: “+num);  }  }  

Output:

num: 5.5

Example 2

In this example, we provide integer value to double variable. Here, compiler implicitly typecast integer to double and display the corresponding value in decimal form.

  public class DoubleExample2 {    public static void main(String[] args) {    double num1=5;  double num2=10;  System.out.println(“num1: “+num1);  System.out.println(“num2: “+num2);  }  }  

Output:

num1: 5.0  num2: 10.0

Example 3

Let’s see an example to test the bigger decimal value.

  public class DoubleExample3 {    public static void main(String[] args) {    double num1=581216732.323433;  double num2=7.83684987683688;  System.out.println(“num1: “+num1);  System.out.println(“num2: “+num2);    }    }  

Output:

num1: 5.81216732323433E8  num2: 7.83684987683688

Example 4

In this example, we provide float value to decimal variable.

  public class DoubleExample4 {    public static void main(String[] args) {            double num1=56.34f;    double num2=34f;  System.out.println(“num1: “+num1);  System.out.println(“num2: “+num2);    }    }  

Output:

num1: 56.34000015258789  num2: 34.0

Example 5

In this example, we provide the maximum range of decimal value.

  public class DoubleExample5 {    public static void main(String[] args) {    double num1=4.94065645841246544e-324d;  double num2=1.79769313486231570e+308d;  System.out.println(“num1: “+num1);  System.out.println(“num2: “+num2);  }  }  

Output:

num1: 4.9E-324  num2: 1.7976931348623157E308

Example 6

In this example, we provide the value in scientific notation

  public class DoubleExample6 {    public static void main(String[] args) {    double num1=1873.2;  //providing same value in scientific notation  double num2=1.8732e3;  System.out.println(“num1: “+num1);  System.out.println(“num2: “+num2);  }    }  

Output:

num1: 1873.2  num2: 1873.2

Example 7

Let’s see an example to create a method of the double return type.

  public class DoubleExample7 {    public double display(double weight)  {  return weight;  }    public static void main(String[] args) {    DoubleExample7 d=new DoubleExample7();  System.out.println(d.display(62.5));  }  }  

Output:

62.5

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Examples of Java double keyword

Example 1

Example 2

Example 3

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Example 5

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