CODEWITHSUNDEEP
c#.netbitbit-shift
user4718239
user4718239

Reputation:

Left shift some bits into a existing number

I have the following existing integer number:

128 = 1000.0000

And I want to shift the following integer number by 2 positions to the left ...

15 = 0000.1111

... into the existing number to bitindex 6:

MyResult should be = 1011.1100 = 188

I've tried this, but the result is wrong. Also if I change the positionsToShift to 2:

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

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

Upvotes: 0

Views: 47

Answers (2)

Dmitrii Bychenko
Dmitrii Bychenko

Reputation: 186688

According your explanations you want numberToLeftShift to shift

  15 << 2

anf then combine with existing integer number:

  (15 << 2) | 128

Implementation

  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;

Upvotes: 3

Hans Kilian
Hans Kilian

Reputation: 25144

According to your textual description, you should use

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

Upvotes: 0

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