Bitwise AND, OR, XOR in C - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to perform a bitwise AND operation between a and b.

C

int result = a [1] b;

Drag options to blanks, or click blank then click option'

A^

B|

C&

D&&

Attempts:

3 left

💡 Hint

Common Mistakes

Using logical AND (&&) instead of bitwise AND (&).

Using bitwise OR (|) instead of AND.

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

2fill in blank

medium

Complete the code to perform a bitwise OR operation between x and y.

C

int combined = x [1] y;

Drag options to blanks, or click blank then click option'

A^

B|

C&

D||

Attempts:

3 left

💡 Hint

Common Mistakes

Using logical OR (||) instead of bitwise OR.

Using bitwise AND (&) instead of OR.

The bitwise OR operator is |. It compares each bit of two numbers and returns 1 if at least one bit is 1.

3fill in blank

hard

Fix the error in the code to perform a bitwise XOR operation between m and n.

C

int diff = m [1] n;

Drag options to blanks, or click blank then click option'

A^

B&

C|

D&&

Attempts:

3 left

💡 Hint

Common Mistakes

Using logical AND (&&) or OR (||) instead of bitwise XOR.

Using bitwise AND (&) or OR (|) instead of XOR.

The bitwise XOR operator is ^. It returns 1 only when the bits are different.

4fill in blank

hard

Fill both blanks to create a mask that keeps only the lower 4 bits of value.

C

int mask = (1 [1] 4) [2] 1;

Drag options to blanks, or click blank then click option'

A<<

B>>

C-

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using right shift (>>) instead of left shift (<<).

Adding 1 instead of subtracting 1.

Shift 1 left by 4 bits to get 16, then subtract 1 to get 15 (binary 1111), which masks the lower 4 bits.

5fill in blank

hard

Fill all three blanks to toggle the 3rd bit of num using XOR.

C

int toggle = num [1] (1 [2] 2 [3] 0);

Drag options to blanks, or click blank then click option'

A&

B^

C<<

D|

Attempts:

3 left

💡 Hint

Common Mistakes

Using AND (&) instead of XOR (^).

Using addition (+) instead of OR (|).

Use XOR (^) to toggle bits. Shift 1 left by 2 to get the 3rd bit mask, then OR (|) to form the mask.

Practice

1. Which bitwise operator in C returns 1 only if both corresponding bits of two numbers are 1?
a & b means:

easy

A. Bitwise AND

B. Bitwise OR

C. Bitwise XOR

D. Logical AND

Solution

1. Step 1: Understand bitwise AND operation

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

2. Step 2: Compare with other operators

   Bitwise OR returns 1 if either bit is 1, XOR returns 1 if bits differ, and logical AND is different (works on boolean values).

3. Final Answer:

   Bitwise AND -> Option A

4. Quick Check:

   AND = & = Bitwise AND [OK]

Hint: AND means both bits must be 1 to get 1 [OK]

Common Mistakes:

• Confusing bitwise AND with logical AND (&&)
• Mixing AND with OR or XOR operators
• Thinking bitwise AND returns 1 if either bit is 1

2. Which of the following is the correct syntax to perform bitwise XOR on two integers a and b in C?

easy

A. a ^ b

B. a && b

C. a | b

D. a & b

Solution

1. Step 1: Identify bitwise XOR operator

   In C, the caret symbol (^) is used for bitwise XOR operation.

2. Step 2: Differentiate from other operators

   && is logical AND, | is bitwise OR, & is bitwise AND, so only ^ is XOR.

3. Final Answer:

   a ^ b -> Option A

4. Quick Check:

   ^ means XOR in C [OK]

Hint: XOR uses ^ symbol in C [OK]

Common Mistakes:

• Using && instead of ^ for XOR
• Confusing | (OR) with ^ (XOR)
• Using & (AND) instead of ^ (XOR)

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

int a = 6;  // binary 0110
int b = 11; // binary 1011
printf("%d", a & b);

medium

A. 3

B. 15

C. 7

D. 2

Solution

1. Step 1: Convert numbers to binary

   6 in binary is 0110, 11 in binary is 1011.

2. Step 2: Perform bitwise AND

   0110 & 1011 = 0010 (only bits where both are 1 remain 1).

3. Step 3: Convert result back to decimal

   0010 in decimal is 2.

4. Final Answer:

   2 -> Option D

5. Quick Check:

   6 & 11 = 2 [OK]

Hint: AND keeps bits set in both numbers only [OK]

Common Mistakes:

• Confusing AND with OR or XOR results
• Not converting binary back to decimal correctly
• Mixing up bit positions

4. Identify the error in this C code snippet that tries to perform bitwise OR:

int a = 5;
int b = 9;
int c = a | b;
printf("%d", c);

medium

A. Missing semicolon after variable declarations

B. Incorrect operator used for bitwise OR

C. No error, code will print correct output

D. printf format specifier should be %x for bitwise OR

Solution

1. Step 1: Check syntax correctness

   All lines have semicolons; operator | is correct for bitwise OR.

2. Step 2: Verify printf usage

   %d is correct to print integer decimal value; no error present.

3. Final Answer:

   No error, code will print correct output -> Option C

4. Quick Check:

   Bitwise OR uses | and %d prints decimal [OK]

Hint: Bitwise OR uses | and %d prints decimal [OK]

Common Mistakes:

• Thinking | is wrong operator for OR
• Believing %x is mandatory for bitwise results
• Missing semicolons (not the case here)

5. Given two integers x = 12 and y = 10, which expression toggles the bits of x where y has bits set, using bitwise XOR?

hard

A. x | y

B. x ^ y

C. x & y

D. ~x ^ y

Solution

1. Step 1: Understand toggling bits with XOR

   Bitwise XOR toggles bits where the second operand has 1s.

2. Step 2: Analyze each option

   x & y keeps bits set in both; x | y sets bits set in either; ~x ^ y is unrelated toggling with complement.

3. Final Answer:

   x ^ y -> Option B

4. Quick Check:

   XOR toggles bits where second operand has 1 [OK]

Hint: XOR toggles bits where second number has 1s [OK]

Common Mistakes:

• Using AND or OR instead of XOR for toggling
• Confusing complement operator ~ with XOR
• Not understanding toggling effect of XOR