Switch statements in C

Question

I am writing a C program with switch statements, and I was wondering if the compiler would accept an operator like

case !('a'): 

I could not find the programs on the Internet that I used ! using the switch statement.

Answer 1

No, I'm sorry, not the way you intend (negation of the entire logical expression, not one of its components). But you can use the default clause to match everything that doesn't match case .

Answer 2

Did you really try?

Well, I did (gcc on Mac OS X).

! is a logical negation operator as well! (x) returns 1 for x from 0 and 0 for anything else. 'a' has a value that is known at compile time, so the compiler evaluates !('a') to 0. So

 case !('a'): 

is equivalent

 case 0 : 

It does not even generate a compiler error and works great.

I believe that this is not what you want to do, and rather you want a case that would catch all the values ​​except "a", and not a single value of 0. Sorry, but the case-switch statements do not work this way, The expression following the case keyword must be a value known to the compiler.

Answer 3

Each condition condition has an int as a conditional value. The symbol is a special case of int. Using the NOT operator does not make sense in a case statement.

The answer is the best answer.