Bit Manipulation Basics AND OR XOR NOT Left Right Shift in DSA Java - Build from Scratch

Bit Manipulation Basics AND OR XOR NOT Left Right Shift

📖 Scenario: You are working with small numbers in a simple calculator program that uses bit manipulation to perform basic operations.Bit manipulation helps computers work fast by changing bits (0s and 1s) directly.

🎯 Goal: Build a Java program that uses bit manipulation operators AND, OR, XOR, NOT, left shift, and right shift on two numbers.You will create variables, set a configuration value, apply bit operations, and print the results.

📋 What You'll Learn

Create two integer variables a and b with exact values 12 and 5

Create an integer variable shift with value 2

Use bitwise AND, OR, XOR, NOT on a and b

Use left shift and right shift on a by shift

Print all results in the exact order: AND, OR, XOR, NOT a, a left shift, a right shift

💡 Why This Matters

🌍 Real World

Bit manipulation is used in low-level programming, graphics, encryption, and performance-critical applications where working directly with bits is faster.

💼 Career

Understanding bitwise operations is important for software engineers working with embedded systems, game development, network programming, and optimization tasks.

1

Create two integer variables a and b

Create two integer variables called a and b with values 12 and 5 respectively.

DSA Java

# Your code here

Hint

Use int a = 12; and int b = 5; to create the variables.

2

Create an integer variable shift with value 2

Create an integer variable called shift and set it to 2.

DSA Java

int a = 12;
int b = 5;
# Your code here

Hint

Use int shift = 2; to create the shift variable.

3

Apply bitwise operations AND, OR, XOR, NOT, left shift, and right shift

Create integer variables andResult, orResult, xorResult, notResult, leftShiftResult, and rightShiftResult to store the results of a & b, a | b, a ^ b, ~a, a << shift, and a >> shift respectively.

DSA Java

int a = 12;
int b = 5;
int shift = 2;
# Your code here

Hint

Use bitwise operators: & for AND, | for OR, ^ for XOR, ~ for NOT, << for left shift, and >> for right shift.

4

Print all bitwise operation results

Print the values of andResult, orResult, xorResult, notResult, leftShiftResult, and rightShiftResult in this exact order, each on its own line.

DSA Java

int a = 12;
int b = 5;
int shift = 2;
int andResult = a & b;
int orResult = a | b;
int xorResult = a ^ b;
int notResult = ~a;
int leftShiftResult = a > shift;
# Your code here

Hint

Use System.out.println() to print each result on its own line in the order given.

Practice

1. What does the bitwise AND operator (&) do when applied to two bits?

easy

A. Flips the bits from 0 to 1 and 1 to 0

B. Returns 1 if at least one bit is 1

C. Returns 1 only if both bits are 1

D. Returns 0 only if both bits are 0

Solution

1. Step 1: Understand bitwise AND operation

   The AND operator compares each bit of two numbers and returns 1 only if both bits are 1.

2. Step 2: Apply to example bits

   For bits 1 & 1, result is 1; for 1 & 0 or 0 & 1 or 0 & 0, result is 0.

3. Final Answer:

   Returns 1 only if both bits are 1 -> Option C

4. Quick Check:

   AND = 1 only if both bits 1 [OK]

Hint: AND returns 1 only when both bits are 1 [OK]

Common Mistakes:

• Confusing AND with OR operator
• Thinking AND flips bits
• Assuming AND returns 1 if any bit is 1

2. Which of the following is the correct syntax for left shifting an integer variable x by 3 positions in Java?

easy

A. x << 3;

B. x >> 3;

C. x <<< 3;

D. x >>> 3;

Solution

1. Step 1: Recall left shift operator syntax in Java

   Left shift operator is << and shifts bits to the left.

2. Step 2: Identify correct usage

   To shift variable x left by 3 bits, use x << 3;. Other options are right shifts or invalid.

3. Final Answer:

   x << 3; -> Option A

4. Quick Check:

   Left shift = x << number [OK]

Hint: Use << for left shift, >> for right shift [OK]

Common Mistakes:

• Using >>> for left shift (it's unsigned right shift)
• Using <<< which is invalid syntax
• Confusing left and right shift operators

3. What is the output of the following Java code?

int a = 5;  // binary 0101
int b = 3;  // binary 0011
int c = a ^ b;
System.out.println(c);

medium

A. 8

B. 7

C. 2

D. 6

Solution

1. Step 1: Convert numbers to binary

   a = 5 is 0101, b = 3 is 0011 in binary.

2. Step 2: Apply XOR operation bitwise

   XOR returns 1 if bits differ, 0 if same.
   0101 XOR 0011 = 0110 (binary) which is 6 decimal.

3. Final Answer:

   6 -> Option D

4. Quick Check:

   5 ^ 3 = 6 [OK]

Hint: XOR sets bits where inputs differ [OK]

Common Mistakes:

• Confusing XOR with OR or AND
• Calculating XOR incorrectly bitwise
• Assuming XOR adds numbers

4. Identify the error in the following Java code snippet:

int x = 8;
int y = ~x << 2;
System.out.println(y);

medium

A. No error; the code runs and prints a valid integer

B. The shift operator << must be used before the NOT operator ~

C. The bitwise NOT operator (~) cannot be used on integers

D. The variable y should be declared as long instead of int

Solution

1. Step 1: Analyze bitwise NOT and shift usage

   The NOT operator (~) flips all bits of x. Then the result is shifted left by 2 bits.

2. Step 2: Check Java syntax and types

   Both ~ and << operators work on int type. The expression is valid and prints an integer.

3. Final Answer:

   No error; the code runs and prints a valid integer -> Option A

4. Quick Check:

   ~ and << valid on int [OK]

Hint: Bitwise NOT and shifts work fine on int in Java [OK]

Common Mistakes:

• Thinking ~ cannot be used on int
• Assuming operator order is wrong
• Believing int can't hold shifted values

5. Given an integer n, which expression correctly toggles (flips) the 4th bit (counting from 0) of n using bitwise operators in Java?

hard

A. n = n | (1 << 4);

B. n = n ^ (1 << 4);

C. n = n & ~(1 << 4);

D. n = ~n << 4;

Solution

1. Step 1: Understand toggling a bit

   Toggling means flipping the bit: 0 becomes 1, 1 becomes 0.

2. Step 2: Identify correct operator for toggling

   XOR (^) with 1 at the bit position flips that bit. So n ^ (1 << 4) toggles the 4th bit.

3. Final Answer:

   n = n ^ (1 << 4); -> Option B

4. Quick Check:

   Toggling bit uses XOR with mask [OK]

Hint: Use XOR with mask to toggle bits [OK]

Common Mistakes:

• Using OR to toggle (only sets bit)
• Using AND with negation to toggle (clears bit)
• Using NOT and shift incorrectly