Bit manipulation techniques - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set the 3rd bit of the variable num.

C

num = num | (1 << [1]);

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

A3

B0

C2

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Using 3 instead of 2 for the bit position.

Confusing bit positions starting from 1 instead of 0.

Bits are counted from 0, so the 3rd bit is at position 2. Shifting 1 by 2 sets the 3rd bit.

2fill in blank

medium

Complete the code to clear (set to 0) the 5th bit of num.

C

num = num & ~(1 << [1]);

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

A4

B5

C3

D6

Attempts:

3 left

💡 Hint

Common Mistakes

Using 5 instead of 4 for the bit position.

Forgetting to negate the mask before AND operation.

The 5th bit is at position 4 (counting from 0). We shift 1 by 4 and then invert it to clear that bit.

3fill in blank

hard

Fix the error in the code to toggle the 1st bit of num.

C

num = num [1] (1 << 0);

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

A|

B^

C&

D>>

Attempts:

3 left

💡 Hint

Common Mistakes

Using AND or OR instead of XOR for toggling.

Using right shift operator which does not toggle bits.

The XOR operator (^) toggles bits. Using it with 1 shifted by 0 toggles the 1st bit.

4fill in blank

hard

Fill both blanks to check if the 4th bit of num is set (1).

C

if ((num [1] (1 << [2])) != 0) {
    // bit is set
}

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

A&

B|

C3

D4

Attempts:

3 left

💡 Hint

Common Mistakes

Using OR instead of AND for checking bits.

Using wrong bit position like 3 instead of 4.

Use bitwise AND (&) with 1 shifted by 4 to check if the 4th bit is set.

5fill in blank

hard

Fill all three blanks to create a mask that keeps only the lower 3 bits of num.

C

mask = (1 << [1]) [2] 1;
result = num [3] mask;

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

A3

B-

C&

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using OR instead of AND to apply the mask.

Using addition instead of subtraction in mask creation.

Using wrong bit count for shifting.

Shift 1 by 3, subtract 1 to get 0b0111 mask. Use AND to keep lower 3 bits.