Java Math.nextAfter() method

The java.lang.Math.nextAfter() returns the floating-point number adjacent to the first argument in the direction of the second argument. If both first argument and second argument are same then this method will return second argument.

Syntax:

public static double nextAfter(double a, double b)
public static float nextAfter(float a, double b)

Parameters:

a = starting floating-point value
b = direction value indicating which of start's neighbors or start should be returned

Return:

This method returns the floating-point number adjacent to start(a) in the direction of b.

If either argument is a NaN, this method will return NaN.
If both arguments are signed zero, the direction will be unchanged.
If start argument(a) is equal to positive or negative Double.MIN_VALUE or Float.MIN_VALUE and direction argument(b) has a value such that the result should have a smaller magnitude, this method will return Zero with same sign as the argument.
If start argument(a) is equal to positive or negative Double.MAX_VALUE or Float.MAX_VALUE and direction argument(b) has a value such that the result should have a lager magnitude, this method will return Infinite with same sign as the argument.
If start argument(a) is infinity and the direction argument(b) has a value such that the result should have a smaller magnitude, then this method will return Double.MAX_VALUE with same sign.

Example 1

public class NextAfterExample1 
{
public static void main(String[] args) 
    	{
      		double a = 84352.24;
      		 double b = 154.284
    		 // print the next number for a towards b
     		 System.out.println(Math.nextAfter(a, b));
      		 // print the next number for b towards a
     		 System.out.println(Math.nextAfter(b, a));
  	  }
}

Test it Now

Output:

84352.23999999999
154.28400000000002

Example 2

public class NextAfterExample2 
{
    public static void main(String[] args) 
    {
        float a = 787.843f;
        double b = 345.56;
        // print the next number for a towards b
         System.out.println(Math.nextAfter(a, b));
    }
}

Test it Now

Output:

787.84296

Example 3

public class NextAfterExample3 
{
    public static void main(String[] args) 
    {
        double a = Double.MIN_VALUE;
        double b = 354.2489;
        System.out.println(Math.nextAfter(a, b));
    }
}

Test it Now

Output:

1.0E-323

Example 4

public class NextAfterExample4 
{
    public static void main(String[] args) 
    {
        float a = Float.MAX_VALUE;
        float b = 793.37f;
        System.out.println(Math.nextAfter(a, b));
    }
}

Test it Now

Output: