Bitwise right shift >> in Objective-C

问题

I have a variable (unsigned int) part_1.

If I do this: NSLog(@"%u %08x", part_1, part_1); (print unsigned value, and hex value) it outputs:

2063597568 7b000000

(only first two will have values).

I want to convert this to

0000007b

So i've tried doing unsigned int part_1b = part_1 >> 6 (and lots of variations)

But this outputs:

32243712 01ec0000

Where am i going wrong?

回答1:

You want to shift by 6*4 = 24 bits, not just 6 bits. Each '0' in the hex printf represents 4 bits.

unsigned int part_1b = part_1 >> 24;
                                 ^^

来源：https://stackoverflow.com/questions/19794519/bitwise-right-shift-in-objective-c