Programming

That's a GREAT question!.

Remember that the "c" variable is an int variable. You are using it to store what we call a "character", but ultimately "c" just holds a number.

What number does it store?

Under the "good" logic, it stores ASCII decimal 65 for 'A', etc. for each character it reads. That is fine.

Under the "bad" logic, it stores a 0 or 1 (equal or unequal). What ASCII characters do 0 or 1 represent? Some weird control character. That's why you get the garbage printed.

Does that make sense to you?

Very much! You also answered my question why int is used for getch() and putch() functions in K&R C_book.

How hard was that bug to see?

That's why it's a bad idea to perform assignments inside the conditional clause of thing like an if statement or while loop.

So what if it saves a line or two of code. Writing quality code is not a contest to see who can stuff the most operations in the least number of lines. Especially given that you wind up with bug-prone and hard-to-understand code.

Agreed! I'm trying to pick up C by myself, not for contest or homework. Thank unix.com, I do not need to go back to school, maybe I'd better do it.

I wouldn't worry about it too much. You're doing fine, it just takes a while when you are learning.

I agree with achenlee that there is too much obscure C code, with stuff jammed on one line. I don't write that way. But you see it a lot. Even K&R frequently emphasizes that style. Many expert programmers are used to that kind of terse code, and seem to like it. So you have to also learn to understand it.