Not operator bitwise java

A quick guide to bitwise operators in Java

Bit manipulation is the direct manipulation of data bits to perform operations and is an important optimization skill now tested by FAANG recruiters. However, this topic is heavily mathematical and is rarely covered in a non-university computer science setting.

Today, we’ll give you a tutorial on bit manipulation and explore some hands-on practice with popular interview questions.

Here’s what we’ll cover today:

Be ready for any bit manipulation question

Practice top asked questions for each bitwise operator with hands-on coding environments.

What is bit manipulation?

Bit manipulation is the process of applying logical operations on a sequence of bits, the smallest form of data in a computer, to achieve a required result. Bit manipulation has constant time complexity and process in parallel, meaning it is very efficient on all systems.

Most programming languages will have you work with abstractions, like objects or variables, rather than the bits they represent. However, direct bit manipulation is needed to improve performance and reduce error in certain situations.

Bit manipulation requires a strong knowledge of binary and binary conversion.

Here’s a few examples of tasks that require bit manipulation:

• Low-level device control
• Error detection and correction algorithms
• Data compression
• Encryption algorithms
• Optimization

For example, take a look at the difference between an arithmetic and bit manipulation approach to finding the green portion of an RGB value:

While both do the same thing, the second option is considerably faster, as it works directly within memory rather than through a level of abstraction.

We’ll explore what each of these operators do later in this article ( >> and & ).

Bitwise Manipulation and Coding Interviews

Bit manipulation is also a common topic in coding interviews, especially with FAANG companies. These interviewers expect you to have a basic understanding of bits, fundamental bit operators, and generally understand the thought process behind bit manipulation.

Having this knowledge demonstrates that you’re a well-rounded developer who understands both the specific tools and the foundation of computer science.

If you’re applying for a role that will work with embedded systems or other low-level systems, you’ll encounter more bit questions. In short, the closer your role is to machine level, the more bit manipulation questions you’ll encounter.

The best way to prepare for bit manipulation questions is to practice using each bitwise operator and brush up on your binary to decimal conversions.

Bitwise Operators

Bitwise operations take one or more bit patterns or binary numerals and manipulate them at the bit level. They’re essentially our tool to manipulate bits to achieve our operations.

While arithmetic operations perform operations on human-readable values ( 1+2 ), bitwise operators manipulate the low-level data directly.

• They are fast and simple actions.
• They are directly supported by the processor.
• They are used to manipulate values for comparisons and calculations.
• Bitwise operations are incredibly simple and faster than arithmetic operations.

Let’s take a quick look at each of the major Bitwise operators and their uses.

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AND Operator

AND ( & ) is a binary operator that compares two operands of equal length. The operands are converted from their readable form to binary representation. For each bit, the operation checks if both bits are 1 across both operands. If yes, that bit is set to 1 in the answer. Otherwise, the corresponding result bit is set to 0.

It essentially multiplies each bit by the corresponding bit in the other operand. As multiplying anything by 0 results in 0 , the AND comparison with any 0 bit will result in 0 .

• If two input bits are 1, the output is 1.
• In all other cases its 0, for example:
  • 1 & 0 => yields to 0.
  • 0 & 1 => yields to 0.
  • 0 & 0 => yields to 0.

   0101 (decimal 5) AND 0011 (decimal 3) 

  The operation may be used to determine whether a particular bit is set (1) or clear (0). It’s also used to clear selected bits of a register in which each bit represents an individual Boolean state.

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  Java — Basic Operators

  There are following relational operators supported by Java language.

  Assume variable A holds 10 and variable B holds 20, then −

  Operator	Description	Example
  == (equal to)	Checks if the values of two operands are equal or not, if yes then condition becomes true.	(A == B) is not true.
  != (not equal to)	Checks if the values of two operands are equal or not, if values are not equal then condition becomes true.	(A != B) is true.
  > (greater than)	Checks if the value of left operand is greater than the value of right operand, if yes then condition becomes true.	(A > B) is not true.
  < (less than)	Checks if the value of left operand is less than the value of right operand, if yes then condition becomes true.	(A < B) is true.
  >= (greater than or equal to)	Checks if the value of left operand is greater than or equal to the value of right operand, if yes then condition becomes true.	(A >= B) is not true.
  	Checks if the value of left operand is less than or equal to the value of right operand, if yes then condition becomes true.	(A

  The Bitwise Operators

  Java defines several bitwise operators, which can be applied to the integer types, long, int, short, char, and byte.

  Bitwise operator works on bits and performs bit-by-bit operation. Assume if a = 60 and b = 13; now in binary format they will be as follows −

  The following table lists the bitwise operators −

  Assume integer variable A holds 60 and variable B holds 13 then −

  Operator	Description	Example
  & (bitwise and)	Binary AND Operator copies a bit to the result if it exists in both operands.	(A & B) will give 12 which is 0000 1100
  | (bitwise or)	Binary OR Operator copies a bit if it exists in either operand.	(A | B) will give 61 which is 0011 1101
  ^ (bitwise XOR)	Binary XOR Operator copies the bit if it is set in one operand but not both.	(A ^ B) will give 49 which is 0011 0001
  ~ (bitwise compliment)	Binary Ones Complement Operator is unary and has the effect of ‘flipping’ bits.	(~A ) will give -61 which is 1100 0011 in 2’s complement form due to a signed binary number.
  	Binary Left Shift Operator. The left operands value is moved left by the number of bits specified by the right operand.	A
  >> (right shift)	Binary Right Shift Operator. The left operands value is moved right by the number of bits specified by the right operand.	A >> 2 will give 15 which is 1111
  >>> (zero fill right shift)	Shift right zero fill operator. The left operands value is moved right by the number of bits specified by the right operand and shifted values are filled up with zeros.	A >>>2 will give 15 which is 0000 1111

  The Logical Operators

  The following table lists the logical operators −

  Assume Boolean variables A holds true and variable B holds false, then −

  Operator	Description	Example
  && (logical and)	Called Logical AND operator. If both the operands are non-zero, then the condition becomes true.	(A && B) is false
  || (logical or)	Called Logical OR Operator. If any of the two operands are non-zero, then the condition becomes true.	(A || B) is true
  ! (logical not)	Called Logical NOT Operator. Use to reverses the logical state of its operand. If a condition is true then Logical NOT operator will make false.	!(A && B) is true

  The Assignment Operators

  Following are the assignment operators supported by Java language −

  Operator	Description	Example
  =	Simple assignment operator. Assigns values from right side operands to left side operand.	C = A + B will assign value of A + B into C
  +=	Add AND assignment operator. It adds right operand to the left operand and assign the result to left operand.	C += A is equivalent to C = C + A
  -=	Subtract AND assignment operator. It subtracts right operand from the left operand and assign the result to left operand.	C -= A is equivalent to C = C – A
  *=	Multiply AND assignment operator. It multiplies right operand with the left operand and assign the result to left operand.	C *= A is equivalent to C = C * A
  /=	Divide AND assignment operator. It divides left operand with the right operand and assign the result to left operand.	C /= A is equivalent to C = C / A
  %=	Modulus AND assignment operator. It takes modulus using two operands and assign the result to left operand.	C %= A is equivalent to C = C % A
  	Left shift AND assignment operator.	C
  >>=	Right shift AND assignment operator.	C >>= 2 is same as C = C >> 2
  &=	Bitwise AND assignment operator.	C &= 2 is same as C = C & 2
  ^=	bitwise exclusive OR and assignment operator.	C ^= 2 is same as C = C ^ 2
  |=	bitwise inclusive OR and assignment operator.	C |= 2 is same as C = C | 2

  Miscellaneous Operators

  There are few other operators supported by Java Language.

  Conditional Operator ( ? : )

  Conditional operator is also known as the ternary operator. This operator consists of three operands and is used to evaluate Boolean expressions. The goal of the operator is to decide, which value should be assigned to the variable. The operator is written as −

  variable x = (expression) ? value if true : value if false

  This will produce the following result −

  Value of b is : 30 Value of b is : 20

  instanceof Operator

  This operator is used only for object reference variables. The operator checks whether the object is of a particular type (class type or interface type). instanceof operator is written as −

  ( Object reference variable ) instanceof (class/interface type)

  If the object referred by the variable on the left side of the operator passes the IS-A check for the class/interface type on the right side, then the result will be true. Following is an example −

  This will produce the following result −

  This operator will still return true, if the object being compared is the assignment compatible with the type on the right. Following is one more example −

  class Vehicle <> public class Car extends Vehicle < public static void main(String args[]) < Vehicle a = new Car(); boolean result = a instanceof Car; System.out.println( result ); >>

  This will produce the following result −

  Precedence of Java Operators

  Operator precedence determines the grouping of terms in an expression. This affects how an expression is evaluated. Certain operators have higher precedence than others; for example, the multiplication operator has higher precedence than the addition operator −

  For example, x = 7 + 3 * 2; here x is assigned 13, not 20 because operator * has higher precedence than +, so it first gets multiplied with 3 * 2 and then adds into 7.

  Here, operators with the highest precedence appear at the top of the table, those with the lowest appear at the bottom. Within an expression, higher precedence operators will be evaluated first.

  Category	Operator	Associativity
  Postfix	expression++ expression—	Left to right
  Unary	++expression –-expression +expression –expression ~ !	Right to left
  Multiplicative	* / %	Left to right
  Additive	+ —	Left to right
  Shift	> >>>	Left to right
  Relational	= instanceof	Left to right
  Equality	== !=	Left to right
  Bitwise AND	&	Left to right
  Bitwise XOR	^	Left to right
  Bitwise OR	|	Left to right
  Logical AND	&&	Left to right
  Logical OR	||	Left to right
  Conditional	?:	Right to left
  Assignment	= += -= *= /= %= ^= |= >= >>>=	Right to left

  What is Next?

  The next chapter will explain about loop control in Java programming. The chapter will describe various types of loops and how these loops can be used in Java program development and for what purposes they are being used.

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