Question

I have

_int8 arr[0] = 0;
_int8 arr[1] = 0;
_int8 arr[2] = 14;
_int8 arr[3] = 16;

I need to convert it to one _int32 using as arr[0] as first part <..> and arr[3] as last.
In the end it should be

_int32 back = 3600;

Should I use bit shifts or smth like that to achieve this?

Answer 1

If you know the byte ordering (i.e. big endian or little endian, check it out on wikipedia), and the array is set up in the right order you can just do:

back = *(_int32 *)arr;

That’ll just interpret your array of 4 bytes as a buffer holding a single 32-bit integer. In your example though, I think you’ve got it set up for big endian and x86 isn’t. So you’d need to swap some bytes.

For instance:

_int32 back = arr[0] << 24 | arr[1] << 16 | arr[2] << 8 | arr[3];

or something like that.