Question

I was just wondering if it was possible to have a variable case using the keyboard? So the cases can be any choice from a to z and its completely variable eg: only choices a),b) and c) appear in one condition bur in another a),b),c),d) and e) might appear. Assume they all call the same function but input a different argument.

    char choice;
int i;
while(true)
{
            // This increments from char 'a' onward to 'b', 'c', 'd', etc.
    for (i = 0; i < number; i++){
            char character = 'a';
            cout << static_cast<char>(character + i) << ") list of choices" << endl;
    }

    cin >> choice;

    switch(choice) {

                    // Same incremental principal to achieve variable cases
        for (i = 0; i < number; i++){
                char character = 'a';
                character = (static_cast<char>(character + i) );

        case character: carryOutJob(argumentDependantOnCharacter);
        }
            }
    }

If I run code similar to this I get errors that look a little something like this:

: error: ‘character’ cannot appear in a constant-expression
: error: jump to case label [-fpermissive]
: error:   crosses initialization of ‘char character’
: error: expected ‘;’ before ‘}’ token
 Error 1

Answer 1

C++ rule say case expression must be constant, so compiler can create code for it at compile time, and beside that if you are checking one character at a time why you don’t use if?