Java - Math nextAfter(double x, double y) method

Description

The Java Math nextAfter(double start, double direction) returns the floating-point number adjacent to the first argument in the direction of the second argument. If both arguments compare as equal the second argument is returned Special cases −

  • If either argument is a NaN, then NaN is returned.

  • If both arguments are signed zeros, direction is returned unchanged (as implied by the requirement of returning the second argument if the arguments compare as equal).

  • If start is Double.MIN_VALUE and direction has a value such that the result should have a smaller magnitude, then a zero with the same sign as start is returned.

  • If start is infinite and direction has a value such that the result should have a smaller magnitude, Double.MAX_VALUE with the same sign as start is returned.

  • If start is equal to Double.MAX_VALUE and direction has a value such that the result should have a larger magnitude, an infinity with same sign as start is returned.

Declaration

Following is the declaration for java.lang.Math.nextAfter() method

public static double nextAfter(double start, double direction)

Parameters

  • start − starting floating-point value

  • direction − value indicating which of start's neighbors or start should be returned

Return Value

This method returns the floating-point number adjacent to start in the direction of direction.

Exception

NA

Example 1

The following example shows the usage of Math nextAfter() method for two positive values.

package com.tutorialspoint;
public class MathDemo {
   public static void main(String[] args) {

      // get two double numbers
      double x = 98759.765;
      double y = 154.28764;
   
      // print the next number for x towards y
      System.out.println("Math.nextAfter(" + x + "," + y + ")="
         + Math.nextAfter(x, y));

      // print the next number for y towards x
      System.out.println("Math.nextAfter(" + y + "," + x + ")="
         + Math.nextAfter(y, x));
   }
}

Output

Let us compile and run the above program, this will produce the following result −

Math.nextAfter(98759.765,154.28764)=98759.76499999998
Math.nextAfter(154.28764,98759.765)=154.28764000000004

Example 2

The following example shows the usage of Math nextAfter() method for a positive and a negative value.

package com.tutorialspoint;
public class MathDemo {
   public static void main(String[] args) {

      // get two double numbers
      double x = -98759.765;
      double y = 154.28764;
   
      // print the next number for x towards y
      System.out.println("Math.nextAfter(" + x + "," + y + ")="
         + Math.nextAfter(x, y));

      // print the next number for y towards x
      System.out.println("Math.nextAfter(" + y + "," + x + ")="
         + Math.nextAfter(y, x));
   }
}

Output

Let us compile and run the above program, this will produce the following result −

Math.nextAfter(-98759.765,154.28764)=-98759.76499999998
Math.nextAfter(154.28764,-98759.765)=154.28763999999998

Example 3

The following example shows the usage of Math nextAfter() method for negative values.

package com.tutorialspoint;
public class MathDemo {
   public static void main(String[] args) {

      // get two double numbers
      double x = -98759.765;
      double y = -154.28764;
   
      // print the next number for x towards y
      System.out.println("Math.nextAfter(" + x + "," + y + ")="
         + Math.nextAfter(x, y));

      // print the next number for y towards x
      System.out.println("Math.nextAfter(" + y + "," + x + ")="
         + Math.nextAfter(y, x));
   }
}

Output

Let us compile and run the above program, this will produce the following result −

Math.nextAfter(-98759.765,-154.28764)=-98759.76499999998
Math.nextAfter(-154.28764,-98759.765)=-154.28764000000004
java_lang_math.htm
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