C Program to Check Whether a Character is a
Vowel or Consonant
In
this example, you will learn to check whether an alphabet entered by the user
is a vowel or a consonant.
To
understand this example, you should have the knowledge of the following C
programming topics:
·
C Programming Operators
·
C if...else Statement
·
C while and do...while Loop
The five letters A
, E
, I
, O
and U
are
called vowels. All other alphabets except these 5 vowels are called consonants.
This
program assumes that the user will always enter an alphabet character.
Program to Check Vowel or
consonant
#include <stdio.h>
int main() {
char c;
int lowercase_vowel, uppercase_vowel;
printf(
"Enter an alphabet: ");
scanf(
"%c", &c);
// evaluates to 1 if variable c is a lowercase vowel
lowercase_vowel = (c ==
'a' || c ==
'e' || c ==
'i' || c ==
'o' || c ==
'u');
// evaluates to 1 if variable c is a uppercase vowel
uppercase_vowel = (c ==
'A' || c ==
'E' || c ==
'I' || c ==
'O' || c ==
'U');
// evaluates to 1 (true) if c is a vowel
if (lowercase_vowel || uppercase_vowel)
printf(
"%c is a vowel.", c);
else
printf(
"%c is a consonant.", c);
return
0;
}
Output
Enter an alphabet: G
G is a consonant.
The character entered by the user is stored in variable c.
The lowercase_vowel variable
evaluates to 1 (true) if c is
a lowercase vowel and 0 (false) for any other characters.
Similarly, the uppercase_vowel variable
evaluates to 1 (true) if c is
an uppercase vowel and 0 (false) for any other character.
If either lowercase_vowel or uppercase_vowel variable
is 1 (true), the entered character is a vowel. However, if both lowercase_vowel and uppercase_vowel variables
are 0, the entered character is a consonant.
Note: This
program assumes that the user will enter an alphabet. If the user enters a
non-alphabetic character, it displays the character is a consonant.
To fix this, we can use the isalpha() function. The islapha()
function
checks whether a character is an alphabet or not.
#include <ctype.h>
#include <stdio.h>
int main() {
char c;
int lowercase_vowel, uppercase_vowel;
printf(
"Enter an alphabet: ");
scanf(
"%c", &c);
// evaluates to 1 if variable c is a lowercase vowel
lowercase_vowel = (c ==
'a' || c ==
'e' || c ==
'i' || c ==
'o' || c ==
'u');
// evaluates to 1 if variable c is a uppercase vowel
uppercase_vowel = (c ==
'A' || c ==
'E' || c ==
'I' || c ==
'O' || c ==
'U');
// Show error message if c is not an alphabet
if (!
isalpha(c))
printf(
"Error! Non-alphabetic character.");
else
if (lowercase_vowel || uppercase_vowel)
printf(
"%c is a vowel.", c);
else
printf(
"%c is a consonant.", c);
return
0;
}
Now, if
the user enters a non-alphabetic character, you will see:
Enter an alphabet: 3
Error! Non-alphabetic character.