二進位制文字

該 0B 字首，可以用來表示二進位制文字。

二進位制文字允許從 0 和 1 構造數字，這使得檢視在數字的二進位制表示中設定哪些位更容易。這對於使用二進位制標誌很有用。

以下是使用值 34（= 2 5 + 2 1 ） 指定 int 的等效方法 ：

// Using a binary literal:
//   bits: 76543210
int a1 = 0b00100010;          // binary: explicitly specify bits

// Existing methods:
int a2 = 0x22;                // hexadecimal: every digit corresponds to 4 bits
int a3 = 34;                  // decimal: hard to visualise which bits are set
int a4 = (1 << 5) | (1 << 1); // bitwise arithmetic: combining non-zero bits

標誌列舉

以前，只能使用此示例中的三種方法之一來指定 enum 的標誌值：

[Flags]
public enum DaysOfWeek
{
    // Previously available methods:
    //          decimal        hex       bit shifting
    Monday    =  1,    //    = 0x01    = 1 << 0
    Tuesday   =  2,    //    = 0x02    = 1 << 1
    Wednesday =  4,    //    = 0x04    = 1 << 2
    Thursday  =  8,    //    = 0x08    = 1 << 3
    Friday    = 16,    //    = 0x10    = 1 << 4
    Saturday  = 32,    //    = 0x20    = 1 << 5
    Sunday    = 64,    //    = 0x40    = 1 << 6

    Weekdays = Monday | Tuesday | Wednesday | Thursday | Friday,
    Weekends = Saturday | Sunday
}

使用二進位制文字，更明顯的是設定哪些位，使用它們不需要理解十六進位制數和按位算術：

[Flags]
public enum DaysOfWeek
{
    Monday    = 0b00000001,
    Tuesday   = 0b00000010,
    Wednesday = 0b00000100,
    Thursday  = 0b00001000,
    Friday    = 0b00010000,
    Saturday  = 0b00100000,
    Sunday    = 0b01000000,

    Weekdays = Monday | Tuesday | Wednesday | Thursday | Friday,
    Weekends = Saturday | Sunday
}