左移一些位到现有数字

Question

我有以下现有的整数：

128 = 1000.0000

我想将下面的整数转移到左边2个位置......

15 = 0000.1111

...将现有数字转换为bitindex 6：

MyResult应为= 1011.1100 = 188

我试过这个，但结果是错的。如果我将positionsToShift更改为2：

int existingNumber = 128;
int numberToLeftShift = 15;
int positionsToShift = 6;

int myResult = (existingNumber << positionsToShift) | numberToLeftShift;

Answer 1

根据您的解释，您希望numberToLeftShift转移

  15 << 2

然后

anf与现有整数结合使用：

  (15 << 2) | 128

实施

  int existingNumber = 128;
  int numberToLeftShift = 15;
  int positionsToShift = 2;   // we want shift by 2 to the left; not by 6

  // numberToLeftShift and existingNumber are swapped
  int myResult = (numberToLeftShift << positionsToShift) | existingNumber;

Answer 2

根据您的文字说明，您应该使用

var myResult = (numberToLeftShift << positionsToShift) | existingNumber;