C# - Bitwise Shift Operators

Shift. In C# this operator moves bit positions. It changes the bit representation of a type. The bits are shifted right (or left) a number of positions.

Operator notes. The C# language enables bitwise shifting with the right and left shift operators. With these operators, individual bits are all moved together.

Bitwise Representation

Bitwise XOR

Input and output. Consider a bit pattern that is part of an integer. We shift to the right several times (the arrows point in the shifting direction).

      101
>> 1: 010
>> 1: 001
>> 1: 000

An example. We introduce a program that shows the right shift and then left shift bitwise operators in the C# language. We repeatedly apply them and change the value of an int.

Info The integer is shifted right zero places, then one place, and then two and more places.

Tip You can see that all numbers that are negative have the very leftmost (first) bit set to 1, while positive numbers have it set to 0.

Note The output of the program illustrates how the bit values are changed with the parameters to the shift operators.

using System;

class Program
{
    static void Main()
    {
        // This program shift an integer right.
        // ... Then it shifts it left.
        // ... It displays the bits and the decimal representation.
        int value1 = 99999999;
        for (int i = 0; i < 32; i++)
        {
            int shift = value1 >> i;
            Console.WriteLine("{0} = {1}",
                GetIntBinaryString(shift), shift);
        }
        for (int i = 0; i < 32; i++)
        {
            int shift = value1 << i;
            Console.WriteLine("{0} = {1}",
                GetIntBinaryString(shift), shift);
        }
    }

    static string GetIntBinaryString(int value)
    {
        // From other article.
        return Convert.ToString(value, 2).PadLeft(32, '0');
    }
}00000101111101011110000011111111 = 99999999
00000010111110101111000001111111 = 49999999
00000001011111010111100000111111 = 24999999
00000000101111101011110000011111 = 12499999
00000000010111110101111000001111 = 6249999
00000000001011111010111100000111 = 3124999
00000000000101111101011110000011 = 1562499
00000000000010111110101111000001 = 781249
00000000000001011111010111100000 = 390624
00000000000000101111101011110000 = 195312
00000000000000010111110101111000 = 97656
00000000000000001011111010111100 = 48828
00000000000000000101111101011110 = 24414
00000000000000000010111110101111 = 12207
00000000000000000001011111010111 = 6103
00000000000000000000101111101011 = 3051
00000000000000000000010111110101 = 1525
00000000000000000000001011111010 = 762
00000000000000000000000101111101 = 381
00000000000000000000000010111110 = 190
00000000000000000000000001011111 = 95
00000000000000000000000000101111 = 47
00000000000000000000000000010111 = 23
00000000000000000000000000001011 = 11
00000000000000000000000000000101 = 5
00000000000000000000000000000010 = 2
00000000000000000000000000000001 = 1
00000000000000000000000000000000 = 0
00000000000000000000000000000000 = 0
00000000000000000000000000000000 = 0
00000000000000000000000000000000 = 0
00000000000000000000000000000000 = 0
00000101111101011110000011111111 = 99999999
00001011111010111100000111111110 = 199999998
00010111110101111000001111111100 = 399999996
00101111101011110000011111111000 = 799999992
01011111010111100000111111110000 = 1599999984
10111110101111000001111111100000 = -1094967328
01111101011110000011111111000000 = 2105032640
11111010111100000111111110000000 = -84902016
11110101111000001111111100000000 = -169804032
11101011110000011111111000000000 = -339608064
11010111100000111111110000000000 = -679216128
10101111000001111111100000000000 = -1358432256
01011110000011111111000000000000 = 1578102784
10111100000111111110000000000000 = -1138761728
01111000001111111100000000000000 = 2017443840
11110000011111111000000000000000 = -260079616
11100000111111110000000000000000 = -520159232
11000001111111100000000000000000 = -1040318464
10000011111111000000000000000000 = -2080636928
00000111111110000000000000000000 = 133693440
00001111111100000000000000000000 = 267386880
00011111111000000000000000000000 = 534773760
00111111110000000000000000000000 = 1069547520
01111111100000000000000000000000 = 2139095040
11111111000000000000000000000000 = -16777216
11111110000000000000000000000000 = -33554432
11111100000000000000000000000000 = -67108864
11111000000000000000000000000000 = -134217728
11110000000000000000000000000000 = -268435456
11100000000000000000000000000000 = -536870912
11000000000000000000000000000000 = -1073741824
10000000000000000000000000000000 = -2147483648

Uses. Each time you use the Dictionary or Hashtable collection or call the GetHashCode method on a string, shift operators are used to acquire the hash code.

Tip You can use a right shift to implement divide by two on positive integral types.

Tip 2 If you are using a data structure that uses bitmasks, bit shifting can be used to guide the control flow.

GetHashCode

Bitwise Divide

Terms. The term "binary operators" is used to describe operators that receive two parameters. A "unary operator" receives only one argument.

Detail The term "bitwise operator" indicates an operator that receives one or two operands. It changes the bit representation.

Summary. We explored the shift operator and how it can be applied to change the value of an integer. The article provides a program to illustrate this clearly through a simulation.