Question

I want to create a siple app which swaps the bytes of 2 and 4 byte hex codes.

So it should do: from 1234 to 3421 swap. I google and found out that I have to use byteorder and CFSwapInt32 and CFSwapInt16.

Here is what I already got:

NSString *byteOrder = [NSString stringWithFormat:@"%d",CFSwapInt32(12345678)];
    NSLog(byteOrder);

But instead of the correct swapped bytes I get: 1315027968 as the number of the NSLog.

Can someone help me or tell me what I did wrong? 🙂 I just want to swap bytes so they are in reversed order

1234 -->3412
12 34 -->34 12

12345678 -->78563412
12 34 56 78 --> 78 56 34 12

Thank you

Answer 1

Try

NSString *byteOrder = [NSString stringWithFormat:@"%x",CFSwapInt32(0x12345678)];

%x will output a value as hexadecimal.

Starting a number with 0x will interpret it as a hexadecimal value.