在当今现代语言的抽象世界里，没有太多。File IO是一个容易想到的方法，尽管它是在已经实现的东西上执行按位操作，而不是实现使用按位操作的东西。尽管如此，作为一个简单的例子，这段代码演示了在c#中删除文件上的只读属性(这样它就可以与指定FileMode.Create的新FileStream一起使用):

//Hidden files posses some extra attibutes that make the FileStream throw an exception
//even with FileMode.Create (if exists -> overwrite) so delete it and don't worry about it!
if(File.Exists(targetName))
{
    FileAttributes attributes = File.GetAttributes(targetName);

    if ((attributes & FileAttributes.ReadOnly) == FileAttributes.ReadOnly)
        File.SetAttributes(targetName, attributes & (~FileAttributes.ReadOnly));

    File.Delete(targetName);
}

As far as custom implementations, here's a recent example: I created a "message center" for sending secure messages from one installation of our distributed application to another. Basically, it's analogous to email, complete with Inbox, Outbox, Sent, etc, but it also has guaranteed delivery with read receipts, so there are additional subfolders beyond "inbox" and "sent." What this amounted to was a requirement for me to define generically what's "in the inbox" or what's "in the sent folder". Of the sent folder, I need to know what's read and what's unread. Of what's unread, I need to know what's received and what's not received. I use this information to build a dynamic where clause which filters a local datasource and displays the appropriate information.

下面是枚举是如何组合在一起的:

    public enum MemoView :int
    {
        InboundMemos = 1,                   //     0000 0001
        InboundMemosForMyOrders = 3,        //     0000 0011
        SentMemosAll = 16,                  //     0001 0000
        SentMemosNotReceived = 48,          //     0011
        SentMemosReceivedNotRead = 80,      //     0101
        SentMemosRead = 144,                //     1001
        Outbox = 272,                       //0001 0001 0000
        OutBoxErrors = 784                  //0011 0001 0000
    }

你明白这是怎么回事了吗?通过与“收件箱”枚举值InboundMemos加上(&)，我知道InboundMemosForMyOrders在收件箱中。

下面是该方法的简化版本，它构建并返回为当前选择的文件夹定义视图的过滤器:

    private string GetFilterForView(MemoView view, DefaultableBoolean readOnly)
    {
        string filter = string.Empty;
        if((view & MemoView.InboundMemos) == MemoView.InboundMemos)
        {
            filter = "<inbox filter conditions>";

            if((view & MemoView.InboundMemosForMyOrders) == MemoView.InboundMemosForMyOrders)
            {
                filter += "<my memo filter conditions>";
            }
        }
        else if((view & MemoView.SentMemosAll) == MemoView.SentMemosAll)
        {
            //all sent items have originating system = to local
            filter = "<memos leaving current system>";

            if((view & MemoView.Outbox) == MemoView.Outbox)
            {
                ...
            }
            else
            {
                //sent sub folders
                filter += "<all sent items>";

                if((view & MemoView.SentMemosNotReceived) == MemoView.SentMemosNotReceived)
                {
                    if((view & MemoView.SentMemosReceivedNotRead) == MemoView.SentMemosReceivedNotRead)
                    {
                        filter += "<not received and not read conditions>";
                    }
                    else
                        filter += "<received and not read conditions>";
                }
            }
        }

        return filter;
    }

非常简单，但在抽象级别上是一个整洁的实现，通常不需要按位操作。

Bit fields (flags) They're the most efficient way of representing something whose state is defined by several "yes or no" properties. ACLs are a good example; if you have let's say 4 discrete permissions (read, write, execute, change policy), it's better to store this in 1 byte rather than waste 4. These can be mapped to enumeration types in many languages for added convenience. Communication over ports/sockets Always involves checksums, parity, stop bits, flow control algorithms, and so on, which usually depend on the logic values of individual bytes as opposed to numeric values, since the medium may only be capable of transmitting one bit at a time. Compression, Encryption Both of these are heavily dependent on bitwise algorithms. Look at the deflate algorithm for an example - everything is in bits, not bytes. Finite State Machines I'm speaking primarily of the kind embedded in some piece of hardware, although they can be found in software too. These are combinatorial in nature - they might literally be getting "compiled" down to a bunch of logic gates, so they have to be expressed as AND, OR, NOT, etc. Graphics There's hardly enough space here to get into every area where these operators are used in graphics programming. XOR (or ^) is particularly interesting here because applying the same input a second time will undo the first. Older GUIs used to rely on this for selection highlighting and other overlays, in order to eliminate the need for costly redraws. They're still useful in slow graphics protocols (i.e. remote desktop).

这些只是我最先想到的几个例子——这不是一个详尽的清单。

数据库世界中的另一个真实应用程序是MySQL，它的数据类型是SET。

位操作符由DBMS存储SET数据类型。设置可以节省空间。

Element    SET Value    Decimal Value
Travel      00000001    1
Sports      00000010    2
Dancing    00000100    4
Fine Dining   00001000  8

我将它们用于多选择选项，这样我只存储一个值，而不是10个或更多

我曾在一些游戏开发书籍中看到它是一种更有效的乘除方法。

2 << 3 == 2 * 8 
32 >> 4 == 32 / 16

低级编程就是一个很好的例子。例如，你可能需要写一个特定的位到内存映射寄存器，以使某些硬件做你想要它做的事情:

volatile uint32_t *register = (volatile uint32_t *)0x87000000;
uint32_t          value;
uint32_t          set_bit   = 0x00010000;
uint32_t          clear_bit = 0x00001000;

value = *register;            // get current value from the register
value = value & ~clear_bit;   // clear a bit
value = value | set_bit;      // set a bit
*register = value;            // write it back to the register

同样，htonl()和htons()是使用&和|操作符实现的(在字节顺序不匹配网络顺序的机器上):

#define htons(a) ((((a) & 0xff00) >> 8) | \
                  (((a) & 0x00ff) << 8))

#define htonl(a) ((((a) & 0xff000000) >> 24) | \
                  (((a) & 0x00ff0000) >>  8) | \
                  (((a) & 0x0000ff00) <<  8) | \
                  (((a) & 0x000000ff) << 24))