设置int中的特定位 [英] Set a specific bit in an int

问题描述

我需要通过为每个可能的数据库值设置int值中的特定位来屏蔽从数据库读取的某些字符串值.例如，如果数据库返回字符串"value1"，则位置0的位将需要设置为1，但是如果数据库返回"value2"，则位置1的位将需要设置为1./p>

如何确保将int的每个位最初设置为0，然后仅打开指定的位?

解决方案

如果您有int值" intValue "，并且想在位置" bitPosition"上设置特定位， em>"，执行以下操作:

intValue = intValue | (1 << bitPosition);

或更短:

intValue |= 1 << bitPosition;

如果您想重置一点(即将其设置为零)，则可以执行以下操作:

intValue &= ~(1 << bitPosition);

(运算符~将值中的每个位取反，因此~(1 << bitPosition)将产生一个 int ，其中除给定位的位外，每个位均为 1 bitPosition .)

I need to mask certain string values read from a database by setting a specific bit in an int value for each possible database value. For example, if the database returns the string "value1" then the bit in position 0 will need to be set to 1, but if the database returns "value2" then the bit in position 1 will need to be set to 1 instead.

How can I ensure each bit of an int is set to 0 originally and then turn on just the specified bit?

解决方案

If you have an int value "intValue" and you want to set a specific bit at position "bitPosition", do something like:

intValue = intValue | (1 << bitPosition);

or shorter:

intValue |= 1 << bitPosition;

If you want to reset a bit (i.e, set it to zero), you can do this:

intValue &= ~(1 << bitPosition);

(The operator ~ reverses each bit in a value, thus ~(1 << bitPosition) will result in an int where every bit is 1 except the bit at the given bitPosition.)

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