Is there really such a thing as a char or short in modern programming?
- by Dean P
Howdy all,
I've been learning to program for a Mac over the past few months (I have experience in other languages). Obviously that has meant learning the Objective C language and thus the plainer C it is predicated on. So I have stumbles on this quote, which refers to the C/C++ language in general, not just the Mac platform.
With C and C++ prefer use of int over
char and short. The main reason behind
this is that C and C++ perform
arithmetic operations and parameter
passing at integer level, If you have
an integer value that can fit in a
byte, you should still consider using
an int to hold the number. If you use
a char, the compiler will first
convert the values into integer,
perform the operations and then
convert back the result to char.
So my question, is this the case in the Mac Desktop and IPhone OS environments? I understand when talking about theses environments we're actually talking about 3-4 different architectures (PPC, i386, Arm and the A4 Arm variant) so there may not be a single answer.
Nevertheless does the general principle hold that in modern 32 bit / 64 bit systems using 1-2 byte variables that don't align with the machine's natural 4 byte words doesn't provide much of the efficiency we may expect.
For instance, a plain old C-Array of 100,000 chars is smaller than the same 100,000 ints by a factor of four, but if during an enumeration, reading out each index involves a cast/boxing/unboxing of sorts, will we see overall lower 'performance' despite the saved memory overhead?
