NOT for inverting bits in Embedded C - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to invert all bits of the variable num using the NOT operator.

Embedded C

unsigned int num = 0x0F; 
unsigned int inverted = [1] num; 

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

A|

B!

C&

D~

Attempts:

3 left

💡 Hint

Common Mistakes

Using ! instead of ~ flips the logic but not the bits.

Using & or | does not invert bits.

The bitwise NOT operator in C is ~. It flips every bit of the number.

2fill in blank

medium

Complete the code to invert bits of value and store the result in result.

Embedded C

unsigned char value = 0xAA; 
unsigned char result = [1]value;

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

A^

B~

C&

D|

Attempts:

3 left

💡 Hint

Common Mistakes

Using & or | operators instead of ~.

Using ^ without a mask does not invert all bits.

The ~ operator inverts all bits of the operand.

3fill in blank

hard

Fix the error in the code to correctly invert bits of data.

Embedded C

unsigned int data = 0x1234;
unsigned int inverted = [1]data;

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

A~

B!

C^

D&

Attempts:

3 left

💡 Hint

Common Mistakes

Using ! instead of ~ causes incorrect results.

Confusing logical and bitwise operators.

The logical NOT operator ! returns 0 or 1, not bitwise inversion. Use ~ for bitwise NOT.

4fill in blank

hard

Fill both blanks to create a mask and invert only the lower 4 bits of num.

Embedded C

unsigned int num = 0x3C;
unsigned int mask = [1];
unsigned int result = num [2] mask;

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

A0x0F

B~

C&

D^

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect mask values.

Using ~ which inverts all bits.

Using & or | which do not flip bits.

Create a mask 0x0F with 1s in the lower 4 bits. XOR (^) the number with this mask inverts exactly those bits (XOR with 1 flips a bit, XOR with 0 leaves it unchanged).

5fill in blank

hard

Fill the blanks to invert bits of value only where mask has 1s, leaving other bits unchanged.

Embedded C

unsigned int value = 0x55AA;
unsigned int mask = [1];
unsigned int result = value [2] mask;
// result now has bits inverted only where mask bits are 1

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

A0x00FF

B^

C~

D&

Attempts:

3 left

💡 Hint

Common Mistakes

Using OR instead of XOR.

Using ~ which inverts all bits unconditionally.

Using & which masks but does not flip.

Use mask 0x00FF to target the lower 8 bits. XOR (^) flips bits where mask is 1.