Programming in C, Switch Case problems

Question

#include <stdio.h>
int main(void)
{
char ch;
//character = ch        
    printf("Please type a character [A-Z or a-z] ('x'to exit):");
    scanf("%c", &ch);   
        switch(ch) //switch statement
        {
        case 'a':
            printf("%c is a vowel.\n", ch);
                break; 
        case 'e':
            printf("%c is a vowel.\n", ch);
                break; 
        case 'i':
            printf("%c is a vowel.\n", ch);
                break; 
        case 'o':
            printf("%c is a vowel.\n", ch);
                break; 
        case 'u':
            printf("%c is a vowel.\n", ch);
                break; 
        case 'A':
            printf("%c is a vowel.\n", ch);
                break; 
        case 'E':
            printf("%c is a vowel.\n", ch);
                break; 
        case 'I':
            printf("%c is a vowel.\n", ch);
                break; 
        case 'O':
            printf("%c is a vowel.\n", ch);
                break; 
        case 'U': 
            printf("%c is a vowel.\n", ch);
                break; 
        default:
            if(ch != 'x'){
                printf("%c is a consonant.\n", ch); 
                    break; }
            else if(ch == 'x'){
                printf("%c is a consonant.\n", ch);
                    break; }
        }   

I have been having much trouble with this code. I have it perfect however it needs to keep repeating until 'x' is entered. Tried a while loop, couldn't have any luck, just recently tried the if statement in the default, that doesnt work either. I'm so close if anyone could give me a little insight!

Answer 1

1. You don't need to repeat yourself so much. You can use multiple labels for a given case:

   case 'a':
   case 'e':
   case 'i':
   case 'o':
   case 'u':
   case 'A':
   case 'E':
   case 'I':
   case 'O':
   case 'U':
       printf("%c is a vowel.\n", ch);
       break;
   default:
       printf("%c is a consonant.\n", ch);
       break;
   

2. You do need a loop:

   do
   {
       printf(...)
       scanf(...)
       switch (...)
       {
          ...
       }
   } while (ch != 'x');
   

3. You might want to add an isalpha call in there before doing the switch at all.

Answer 2

while(ch != 'x'){
  ...

  ...
}

or maybe you can do a function menu approach

void runMenu(){
     // do stuff
     runMenu();
}

I would look at @Carl Norum's answer for code optimization!