#include<stdio.h>
#include<conio.h>
void main()
{
	char ch;

    printf("Enter a character\t:");
    scanf("%c",&ch);

    (ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u' || ch == 'A' || ch == 'E' || ch == 'I' || ch == 'O' || ch == 'U') ? printf("\nEntered character is a vowel") : printf("\nEntered character is not a vowel");

    getch();
}

********** Run1 ********** 

Enter a character       :g

Entered character is not a vowel


********** Run2 ********** 

Enter a character       :E

Entered character is a vowel

General Form of Ternary Operator (conditional operator):
(expression_1) ? (expression_2) : (expression_3);

expression_1 is a comparison/conditional argument. If expression_1 results in true then, expression_2 is executed/returned, and if expression_1 results in false then, expression_3 gets executed/returned.



To check whether a character is a vowel, we have to check for both uppercase and lowercase vowels i.e. a,e,i,o,u,A,E,I,O and U
Condition for checking is
if(ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u' || ch == 'A' || ch == 'E' || ch == 'I' || ch == 'O' || ch == 'U')
Note that Character in C is represented inside single quote. Do not forget to add single quote whenever checking for character constant.

Using conditional operator, this is done as follows:
(ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u' || ch == 'A' || ch == 'E' || ch == 'I' || ch == 'O' || ch == 'U') ? printf("\nEntered character is a vowel") : printf("\nEntered character is not a vowel");



If entered character is among these alphabets (a, e, i, o, u, A, E, I, O, U) then condition in expression_1 evaluates to true, and, statement in expression_2 printf("\nEntered character is a vowel") is executed.
If entered character is not one of these alphabets the condition evaluates to false, and, statement in expression_3 printf("\nEntered character is not a vowel") is executed.