In C, bitwise operators are used to manipulate individual bits of integer values. They perform operations at the bit level, allowing you to perform tasks such as bit shifting, setting or clearing specific bits, or combining multiple bits together. C provides several bitwise operators that can be used:
- Bitwise AND (
&): Performs a bitwise AND operation between two operands. It compares each bit of the first operand with the corresponding bit of the second operand and sets the resulting bit to 1 if both bits are 1; otherwise, it sets the resulting bit to 0. - Bitwise OR (
|): Performs a bitwise OR operation between two operands. It compares each bit of the first operand with the corresponding bit of the second operand and sets the resulting bit to 1 if at least one of the bits is 1; otherwise, it sets the resulting bit to 0. - Bitwise XOR (
^): Performs a bitwise exclusive OR operation between two operands. It compares each bit of the first operand with the corresponding bit of the second operand and sets the resulting bit to 1 if the bits are different; otherwise, it sets the resulting bit to 0. - Bitwise NOT (
~): Performs a bitwise NOT operation on a single operand. It flips each bit of the operand, changing 1s to 0s and 0s to 1s. - Left shift (
<<): Shifts the bits of the left operand to the left by a specified number of positions. The leftmost bits are discarded, and the rightmost bits are filled with zeros. - Right shift (
>>): Shifts the bits of the left operand to the right by a specified number of positions. The rightmost bits are discarded, and the leftmost bits are filled based on the type of the value being shifted (logical shift for unsigned types, arithmetic shift for signed types).
These bitwise operators can be used with integer types (int, char, short, long, etc.) to manipulate individual bits of the values. They are particularly useful for tasks such as bit manipulation, bitwise flags, and low-level programming.
Bitwise AND operator:
The bitwise AND operator (&) in C performs a bitwise AND operation between two operands. It compares each bit of the first operand with the corresponding bit of the second operand and sets the resulting bit to 1 if both bits are 1; otherwise, it sets the resulting bit to 0.
The syntax for the bitwise AND operator is:
result = operand1 & operand2;
Here, operand1 and operand2 are the values on which the bitwise AND operation is performed, and result is the variable that stores the result of the operation.
Let’s take an example to illustrate how the bitwise AND operator works:
unsigned int a = 10; // Binary: 1010
unsigned int b = 6; // Binary: 0110
unsigned int result = a & b;
printf("Result: %u\n", result); // Output: Result: 2
In this example, a and b are unsigned integers. The binary representation of a is 1010, and the binary representation of b is 0110. Performing the bitwise AND operation on a and b gives the result 0010, which is 2 in decimal representation.
Note that the bitwise AND operator is commonly used for bit masking and clearing specific bits in a value. By ANDing a value with a bitmask that has specific bits set to 1 and others set to 0, you can isolate and manipulate specific bits while leaving the remaining bits unchanged.
Bitwise OR operator:
The bitwise OR operator (|) in C performs a bitwise OR operation between two operands. It compares each bit of the first operand with the corresponding bit of the second operand and sets the resulting bit to 1 if at least one of the bits is 1; otherwise, it sets the resulting bit to 0.
The syntax for the bitwise OR operator is:
result = operand1 | operand2;
Here, operand1 and operand2 are the values on which the bitwise OR operation is performed, and result is the variable that stores the result of the operation.
Let’s take an example to illustrate how the bitwise OR operator works:
unsigned int a = 10; // Binary: 1010
unsigned int b = 6; // Binary: 0110
unsigned int result = a | b;
printf("Result: %u\n", result); // Output: Result: 14
In this example, a and b are unsigned integers. The binary representation of a is 1010, and the binary representation of b is 0110. Performing the bitwise OR operation on a and b gives the result 1110, which is 14 in decimal representation.
The bitwise OR operator is commonly used for setting specific bits in a value. By ORing a value with a bitmask that has specific bits set to 1, you can set those bits to 1 while leaving the remaining bits unchanged. It can also be used for combining or merging bit flags or options.
Bitwise exclusive OR operator:
The bitwise exclusive OR operator (XOR) (^) in C performs a bitwise exclusive OR operation between two operands. It compares each bit of the first operand with the corresponding bit of the second operand and sets the resulting bit to 1 if the bits are different; otherwise, it sets the resulting bit to 0.
The syntax for the bitwise XOR operator is:
result = operand1 ^ operand2;
Here, operand1 and operand2 are the values on which the bitwise XOR operation is performed, and result is the variable that stores the result of the operation.
Let’s take an example to illustrate how the bitwise XOR operator works:
unsigned int a = 10; // Binary: 1010
unsigned int b = 6; // Binary: 0110
unsigned int result = a ^ b;
printf("Result: %u\n", result); // Output: Result: 12
In this example, a and b are unsigned integers. The binary representation of a is 1010, and the binary representation of b is 0110. Performing the bitwise XOR operation on a and b gives the result 1100, which is 12 in decimal representation.
The bitwise XOR operator is commonly used for flipping or toggling specific bits in a value. By XORing a value with a bitmask that has specific bits set to 1, you can toggle those bits, changing 1s to 0s and 0s to 1s, while leaving the remaining bits unchanged. It can also be used for bitwise arithmetic and encryption algorithms.
Bitwise complement operator:
The bitwise complement operator (~) in C is a unary operator that performs a bitwise NOT operation on a single operand. It flips each bit of the operand, changing 1s to 0s and 0s to 1s.
The syntax for the bitwise complement operator is:
result = ~operand;
Here, operand is the value on which the bitwise complement operation is performed, and result is the variable that stores the result of the operation.
Let’s take an example to illustrate how the bitwise complement operator works:
unsigned int a = 10; // Binary: 0000000000001010
unsigned int result = ~a;
printf("Result: %u\n", result); // Output: Result: 4294967285
In this example, a is an unsigned integer with the binary representation of 0000000000001010. Performing the bitwise complement operation on a gives the result 1111111111110101, which is 4294967285 in decimal representation.
It’s important to note that the bitwise complement operator operates on the individual bits of the operand and doesn’t consider the sign or the size of the operand. The resulting value is always an unsigned integer.
The bitwise complement operator is commonly used for bitwise negation, flipping all the bits of a value. It can be used for various purposes, including creating bit masks or performing bitwise operations.
Bitwise shift operators:
The bitwise shift operators (<< and >>) in C are used to shift the bits of a value to the left or right by a specified number of positions. These operators are commonly used for manipulating binary data and performing various bitwise operations.
The left shift operator (<<) shifts the bits of a value to the left by a specified number of positions, filling the empty bits with zeros. The syntax for the left shift operator is:
result = operand << shift_amount;
Here, operand is the value to be shifted, shift_amount is the number of bit positions to shift, and result is the variable that stores the result of the operation.
Let’s take an example to illustrate how the left shift operator works:
unsigned int a = 10; // Binary: 0000000000001010
unsigned int result = a << 2;
printf("Result: %u\n", result); // Output: Result: 40
In this example, a is an unsigned integer with the binary representation of 0000000000001010. Shifting a to the left by 2 positions using the left shift operator gives the result 0000000000101000, which is 40 in decimal representation.
The right shift operator (>>) shifts the bits of a value to the right by a specified number of positions. If the value is an unsigned type, the empty bits are filled with zeros; otherwise, the empty bits are filled with the sign bit (the leftmost bit) of the original value. The syntax for the right shift operator is:
result = operand >> shift_amount;
Here, operand is the value to be shifted, shift_amount is the number of bit positions to shift, and result is the variable that stores the result of the operation.
Let’s take an example to illustrate how the right shift operator works:
unsigned int a = 10; // Binary: 0000000000001010
unsigned int result = a >> 2;
printf("Result: %u\n", result); // Output: Result: 2
In this example, a is an unsigned integer with the binary representation of 0000000000001010. Shifting a to the right by 2 positions using the right shift operator gives the result 0000000000000010, which is 2 in decimal representation.
The bitwise shift operators are commonly used for manipulating binary data, creating bit masks, or performing various bitwise operations, such as division or multiplication by powers of 2. It’s important to note that shifting a value too far can cause it to overflow or underflow, resulting in unexpected behavior.