The java.lang.Integer.reverse() is an inbuilt method in Java and is used to return the reverse order of the bits in the two’s complement binary representation of the specified int value.
Syntax:
public static int reverse(int a)
Parameters: The parameter a is an integer value whose bits are to be reversed.
Return Value: The method returns the value which is obtained by reversing the order of the bits in the specified int value.
Examples:
Input: 86 Output: 1778384896 Explanation: Consider an integer a = 86 Binary Representation = 1010110 The number of one bit = 4 After reversing it is = 1778384896 Input: 168 Output: 352321536
Below programs illustrate the java.lang.Integer.reverse() method:
Program 1: For a positive number.
// Java program to illustrate the// Java.lang.Integer.reverse() methodimport java.lang.*; public class geeks { public static void main(String[] args) { int a = 168; System.out.println("Number = " + a); // It returns the value obtained by reversing order of the bits System.out.println("By reversing we get = " + Integer.reverse(a)); }} |
Output:
Number = 168 By reversing we get = 352321536
Program 2: For a Negative number.
// Java program to illustrate the// Java.lang.Integer.reverse() methodimport java.lang.*; public class geeks { public static void main(String[] args) { int a = -72; System.out.println("Number = " + a); // It returns the value obtained by reversing order of the bits System.out.println("By reversing we get = " + Integer.reverse(a)); }} |
Output:
Number = -72 By reversing we get = 503316479
Program 3: For a decimal value and string.
Note: It throws an error message when a decimal value or string is passed as an argument.
// Java program to illustrate the// Java.lang.Integer.reverse() methodimport java.lang.*; public class geeks { public static void main(String[] args) { int a = 37.9; System.out.println("Number = " + a); // It returns the value obtained by reversing order of the bits in // the specified int value System.out.println("By reversing we get = " + Integer.reverse(a)); a = "21"; System.out.println("Number = " + a); // It returns the value obtained by reversing order of the bits in // the specified int value System.out.println("By reversing we get = " + Integer.reverse(a)); }} |
Output:
prog.java:9: error: incompatible types: possible lossy conversion from double to int
int a = 37.9;
^
prog.java:17: error: incompatible types: String cannot be converted to int
a = "21";
^
2 errors
