evaluate multiple variables in a if [closed] statement

  

But this leaves me with an ugly code in which I have to use the letter I'm checking many times, try to do this:

if(letra1, letra2, letra3, letra4, letra5, letra6 != a){                        
    again, after, about = 0;
}

     

But C ++ seems not to read that as I expected.

The way in which this instruction is interpreted in C ++ is the following: each of the expressions separated by a comma is evaluated and all except the last one are discarded. That is, it evaluates letra1 and discards it, letra2 and discards it, until it reaches letra6 != a and uses it as a result of the complete expression.

This is the behavior of the operator comma , .

What you intend to do is not possible in C ++, that is: there is no way to simplify that kind of comparison 1 . What you can do is compare in another way, for example by saving the letters you want to compare in a 2 formation and operating on it:

char letras[] {letra1, letra2, letra3, letra4, letra5, letra6};

if (std::count(std::begin(letras), std::end(letras), 'a') == 0) {
    // Ninguna letra es 'a'
}

It occurs to me that you could use a switch case:

switch(a){
    case letra1:
    case letra2:
    case letra3:
    case letra4:
    case letra5:
    case letra6:
        break;
    default:
        again, after, about = 0;
        break;
}

What you can do is create a separate method to check the condition and call it whenever you need it:

public bool condicion(String letra){
   if(letra1 != letra && letra2 != letra && letra3 != letra && letra4 != letra && letra5 != letra && letra6 != letra){
      return true;
   }
   return false;
}

Now to use it in a method:

if(condicion("a")){           
   again, after, about = 0
} 

And so all right.