Question

A char in the C programming language is a fixed-size byte entity designed specifically to be large enough to store a character value from an encoding such as ASCII.

But to what extent are the integer values relating to ASCII encoding interchangeable with the char characters? Is there any way to refer to ‘A’ as 65 (decimal)?

getchar() returns an integer – presumably this relates directly to such values? Also, if I am not mistaken, it is possible in certain contexts to increment chars … such that (roughly speaking) ‘?’+1 == ‘@’.

Or is such encoding not guaranteed to be ASCII? Does it depend entirely upon the particular environment? Is such manipulation of chars impractical or impossible in C?

Edit: Relevant: C comparison char and int

Answer 1

But to what extent are the integer values relating to ASCII encoding interchangeable with the char characters? Is there any way to refer to ‘A’ as 65 (decimal)?

In fact, you can’t do anything else. char is just an integral type, and if you write

char ch = 'A';

then (assuming ASCII), ch will merely hold the integer value 65 – presenting it to the user is a different problem.

Or is such encoding not guaranteed to be ASCII?

No, it isn’t. C doesn’t rely on any specific character encoding.

Does it depend entirely upon the particular environment?

Yes, pretty much.

Is such manipulation of chars impractical or impossible in C?

No, you just have to be careful and know the standard quite well – then you’ll be safe.