Hello

char can indeed be treated as a number type. In fact, it is a number type. Various utility functions might be designed to act as though it is a character, but as far as the compiler is concerned, it is a number type, and thus math operators and such will work as expected.

Given that, though, I would suggest that you use int anyway. True, a char is (typically) four times smaller, but in many stages of execution (such as when the number is being operated on by the processor), it is going to be the same size as an int anyway. The only thing you might be saving is a few bytes in RAM or on the hard drive (if you save it to a file). And until you get pretty large programs, a few bytes is going to be majorly insignificant.

Stick with good style and quality of code before ever worrying about performance. As you become better and more experienced at programming, you might begin to develop a good intuition for when you can worry about performance early on, but as you're learning, it is a very wise thing to worry far far more about good style/readability than it is about performance. And in the later stages of learning, when you do begin to worry more about performance, it will mostly focus around general algorithmic issues, rather than minor things such as "Should I use chars instead of ints?" or "Should I use bit-shifts instead of multiplies?" Only when you really really know what you're doing should you worry much about "micro-optimizations" such as this, because at that point, you'll know better whether it is indeed worth it or not.

you can use an unsigned char to store values from 0-255. But be aware that if you write that varialbe to a file it would (likely) be written as a character symbol, this is only a problem if the file is supposed to be human-readable (a person would see a symbol rather than a number) - ofcourse when reading the file again later the symbol would be read back into the char and used a number again.

In C++ you would not need to type-cast a char to an int in order to perform operations on it.

I think that in this case case, the decision to use a char rather than an int for the sole purpose of saving memory is barely worth worrying about - You would (probably) save 3-bytes of memory which is practicaly nothing on modern computers and consoles.

NOTE: Please do-not assume that a char is a signed char, it might well be an unsigned char! The decision is completely up to the compiler not the C++ standard!

As far as I remember (from somewhere deep in the back of my mind) chars and unsigned chars are converted to ints (and presumably unsigned ints) when doing arithmetic so you don't have to type cast them to ints to avoid overflows. I might be wrong so I recommend experimenting. Otherwise, what Agony said. You shouldn't worry about it unless you have a space problem.