Bit Manipulation Basics AND OR XOR NOT Left Right Shift in DSA C - Practice Problems & Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of Bitwise AND and OR Operations

What is the output of the following C code snippet?

DSA C

int a = 12;  // binary: 1100
int b = 10;  // binary: 1010
int c = a & b;
int d = a | b;
printf("%d %d", c, d);

A 4 14

B 8 14

C 8 12

D 4 12

💡 Hint

Remember that & compares bits and returns 1 only if both bits are 1; | returns 1 if either bit is 1.

12 in binary is 1100, 10 is 1010.

AND: 1100 & 1010 = 1000 (8 decimal)

OR: 1100 | 1010 = 1110 (14 decimal)

❓ Predict Output

intermediate

Result of Bitwise XOR and NOT Operations

What will be printed by this C code?

DSA C

unsigned char x = 5;  // binary: 00000101
unsigned char y = 9;  // binary: 00001001
unsigned char z = x ^ y;
unsigned char w = ~x;
printf("%u %u", z, w);

A 1 250

B 13 250

C 12 250

D 12 251

💡 Hint

XOR returns 1 when bits differ; NOT flips all bits in the byte.

5 (00000101) XOR 9 (00001001) = 00001100 (12 decimal)

NOT 5 flips bits: 11111010 (250 decimal for unsigned char)

❓ Predict Output

advanced

Left and Right Shift Effects on Signed Integers

What is the output of this C code snippet?

DSA C

int a = -16;  // binary (32-bit): 11111111 11111111 11111111 11110000
int b = a >> 2;
int c = a << 2;
printf("%d %d", b, c);

A -4 -64

B -4 64

C 1073741820 -64

D 4 64

💡 Hint

Right shift of negative signed integers usually fills with sign bit; left shift multiplies by powers of two.

Right shift -16 by 2: -16 / 4 = -4 (arithmetic shift)

Left shift -16 by 2: -16 * 4 = -64

❓ Predict Output

advanced

Output with Mismatched Format Specifier on Bitwise NOT

What is the output of the following C code snippet? (Note: may produce compiler warning)

DSA C

int x = 1;
int y = ~x;
printf("%u", y);

A -2

B Runtime error

C Compilation error due to format specifier mismatch

D 4294967294

💡 Hint

Consider the bit pattern of ~1 (0xFFFFFFFE) when printed with %u (unsigned int).

~1 produces 0xFFFFFFFE, which is -2 as signed int but 4294967294 as unsigned int.

%u expects unsigned int, leading to this output (with compiler warning).

🧠 Conceptual

expert

Understanding Bitwise Shift on Unsigned Integers

Given unsigned int x = 1; what is the value of x after the operation x = x << 31; ?

A 2147483648

B 0

C 1

D Undefined behavior

💡 Hint

Left shifting 1 by 31 bits sets the highest bit in a 32-bit unsigned integer.

1 shifted left 31 bits becomes 2^31 = 2147483648.

For unsigned int, this is well-defined.