Problems with case 'p' || 'P': syntax within a switch statement in C++

Question

I\'ve used the switch statement the following way:

   switch (ch){
   case \'P\' || \'p\': 
        goto balance;
        break;

   case \'r\' || \'R\':
           


        

Answer 1

Change it to

case 'P':
case 'p': 
    goto balance;
    break;

Using goto is usually not a good idea.

---

In your original code, case 'P' || 'p': is equivalent to case 1 as the result of || is 0 if both operand are zero, or 1 otherwise. So in the two case statement, both 'p' || 'P' and 'r' || 'R' evaluated as 1, that's why you got the warning about duplicate case value.

Answer 2

|| is a binary operator; 'P' || 'p' evaluates to true, because the left-hand operand of || is non-zero. Same thing for 'R' || 'r'. So both case statements are case true:, and that's what the compiler is complaining about. Separate the values:

case 'P':
case 'p':
    menu(); // function call recommended instead of `goto`
    break;

Answer 3

case 'P' || 'p': 
    ...

was meant to be:

case 'P':
case 'p':
    ...

---

Note that there is another (in this case more reasonable) approach you could use:

switch ( std::tolower(ch) ) {
case 'p': 
     ...
     break;
case 'r':
     ...
     break; 

default:
     ...
}

you'll just have to #include <cctype>