Bitwise operators in C# allow you to manipulate individual bits within integer types, such as int, uint, long, ulong, byte, and sbyte.
They are commonly used in low-level programming, data compression, cryptography, and optimization tasks.
In this tutorial, we’ll cover:
1. Overview of Bitwise Operators
Here’s a quick overview of bitwise operators in C#:
| Operator | Description | Example |
|---|---|---|
| & | Bitwise AND | a & b |
| ` | ` | Bitwise OR |
| ^ | Bitwise XOR (exclusive OR) | a ^ b |
| ~ | Bitwise NOT (one’s complement) | ~a |
| << | Left shift | a << n |
| >> | Right shift | a >> n |
These operators work at the bit level, so they are used primarily with integer types in C#.
2. Bitwise AND (&)
The & (AND) operator compares each bit of its operands. It returns 1 if both bits are 1; otherwise, it returns 0.
Example:
using System;
public class BitwiseAndExample
{
public static void Main()
{
int a = 6; // Binary: 110
int b = 3; // Binary: 011
int result = a & b; // Result: 2 (Binary: 010)
Console.WriteLine("a & b = " + result);
}
}
Explanation:
- 6 in binary is 110.
- 3 in binary is 011.
- 6 & 3 results in 010 (binary for 2) because only the second bit from the right has both bits as 1.
Output:
a & b = 2
3. Bitwise OR (|)
The | (OR) operator compares each bit of its operands. It returns 1 if at least one of the bits is 1; otherwise, it returns 0.
Example:
using System;
public class BitwiseOrExample
{
public static void Main()
{
int a = 6; // Binary: 110
int b = 3; // Binary: 011
int result = a | b; // Result: 7 (Binary: 111)
Console.WriteLine("a | b = " + result);
}
}
Explanation:
- 6 in binary is 110.
- 3 in binary is 011.
- 6 | 3 results in 111 (binary for 7) because each bit position has at least one 1.
Output:
a | b = 7
4. Bitwise XOR (^)
The ^ (XOR) operator compares each bit of its operands. It returns 1 if the bits are different; otherwise, it returns 0.
Example:
using System;
public class BitwiseXorExample
{
public static void Main()
{
int a = 6; // Binary: 110
int b = 3; // Binary: 011
int result = a ^ b; // Result: 5 (Binary: 101)
Console.WriteLine("a ^ b = " + result);
}
}
Explanation:
- 6 in binary is 110.
- 3 in binary is 011.
- 6 ^ 3 results in 101 (binary for 5) because only the bits in each position differ.
Output:
a ^ b = 5
5. Bitwise NOT (~)
The ~ (NOT) operator inverts each bit of its operand, turning 1s to 0s and 0s to 1s. This is known as a bitwise complement.
Example:
using System;
public class BitwiseNotExample
{
public static void Main()
{
int a = 6; // Binary: 0000 0110 (32-bit integer representation)
int result = ~a; // Result: -7 (Binary: 1111 1001 for signed int)
Console.WriteLine("~a = " + result);
}
}
Explanation:
- 6 in binary is 0000 0110.
- ~6 inverts the bits, resulting in 1111 1001, which is -7 in a signed integer representation due to two’s complement notation.
Output:
~a = -7
6. Left Shift (<<) and Right Shift (>>)
The shift operators move the bits to the left or right by a specified number of positions.
- Left Shift (<<): Shifts bits to the left, filling the rightmost bits with zeros.
- Right Shift (>>): Shifts bits to the right, filling the leftmost bits with the sign bit (for signed types).
Example: Left Shift
using System;
public class LeftShiftExample
{
public static void Main()
{
int a = 3; // Binary: 0000 0011
int result = a << 2; // Result: 12 (Binary: 0000 1100)
Console.WriteLine("a << 2 = " + result);
}
}
Explanation:
- 3 in binary is 0000 0011.
- Shifting left by 2 positions results in 0000 1100 (binary for 12).
Output:
a << 2 = 12
Example: Right Shift
using System;
public class RightShiftExample
{
public static void Main()
{
int a = 12; // Binary: 0000 1100
int result = a >> 2; // Result: 3 (Binary: 0000 0011)
Console.WriteLine("a >> 2 = " + result);
}
}
Explanation:
- 12 in binary is 0000 1100.
- Shifting right by 2 positions results in 0000 0011 (binary for 3).
Output:
a >> 2 = 3
7. Practical Examples of Bitwise Operators
Example 1: Checking Odd or Even
You can use the bitwise AND operator to check if a number is odd or even.
using System;
public class OddEvenCheck
{
public static void Main()
{
int number = 7;
if ((number & 1) == 1)
{
Console.WriteLine("The number is odd.");
}
else
{
Console.WriteLine("The number is even.");
}
}
}
Explanation:
- The expression number & 1 checks the least significant bit. If it’s 1, the number is odd; otherwise, it’s even.
Output:
The number is odd.
Example 2: Swapping Two Numbers Using XOR
You can use the XOR operator to swap two numbers without a temporary variable.
using System;
public class SwapUsingXor
{
public static void Main()
{
int x = 5;
int y = 10;
x = x ^ y;
y = x ^ y;
x = x ^ y;
Console.WriteLine("After swapping: x = " + x + ", y = " + y);
}
}
Explanation:
- XOR swapping allows x and y to be swapped without a temporary variable by combining the XOR operations.
Output:
After swapping: x = 10, y = 5
Example 3: Setting and Clearing Specific Bits
You can use bitwise operators to set, clear, or toggle specific bits in a number.
using System;
public class BitManipulationExample
{
public static void Main()
{
int num = 8; // Binary: 1000
int bitToSet = 1; // Second bit (Binary: 0010)
int setResult = num | bitToSet; // Set second bit
int clearResult = num & ~bitToSet; // Clear second bit
Console.WriteLine("Set second bit: " + Convert.ToString(setResult, 2));
Console.WriteLine("Clear second bit: " + Convert.ToString(clearResult, 2));
}
}
Explanation:
- Set bit: num | bitToSet uses OR to set the second bit.
- Clear bit: num & ~bitToSet uses AND with the inverted bit mask to clear the second bit.
Output:
Set second bit: 1010 Clear second bit : 1000
Summary
Bitwise operators in C# allow manipulation of individual bits within numbers. Here’s a recap:
- AND (&): Returns 1 if both bits are 1.
- OR (|): Returns 1 if at least one bit is 1.
- XOR (^): Returns 1 if the bits differ.
- NOT (~): Inverts each bit.
- Left Shift (<<): Shifts bits to the left, padding with zeros.
- Right Shift (>>): Shifts bits to the right, filling with the sign bit.