Question

Hey take a look at the code:

#define SUFFIX(n)  (switch(n)                                               \
                   {                                                        \
                        case 1: printf("st\n");                             \
                        break;                                              \
                                                                            \
                        case 2: printf("nd\n");                             \
                        break;                                              \
                                                                            \
                        case 3: printf("rd\n");                             \
                        break;                                              \
                   }                                                        \
                   )                                                        

calling the above macro in main:

int main()
{
    printf("%s", suffix(1));
}

But when I call this I get a error message:

expected expression before switch

But what expression am I missing?

Answer 1

What you’re trying to do won’t work. switch is a statement but printf requires an expression.

Option 1:

Remove the brackets () from your #define and simply say SUFFIX(1) without the printf.

#define SUFFIX(n)  switch(n)                                               \
                   { case 1: printf("st\n"); break;                        \
                     case 2: printf("nd\n"); break;                        \
                     case 3: printf("rd\n"); break;                        \
                   }
int main()
{
    SUFFIX(1);
}

Option 2:

#define SUFFIX(n) ( n == 1 ? "st" : (n == 2 ? "nd" : (n == 3 ? "rd" : "")) )
int main()
{
  printf("%s", SUFFIX(1));
}

Option 3 and 4:

Make one of the above a function. The first returns void, the second returns char *.