Five alphabets a, e, i, o and u are known as vowels. All other alphabets except these 5 alphabets are known as consonants.
This program assumes that the user will always enter an alphabet.
Example: Check Vowel or a Consonant Manually
#include <iostream>
using namespace std;
int main() {
char c;
bool isLowercaseVowel, isUppercaseVowel;
cout << "Enter an alphabet: ";
cin >> c;
// evaluates to 1 (true) if c is a lowercase vowel
isLowercaseVowel = (c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u');
// evaluates to 1 (true) if c is an uppercase vowel
isUppercaseVowel = (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 (isLowercaseVowel || isUppercaseVowel)
cout << c << " is a vowel.";
else
cout << c << " is a consonant.";
return 0;
}
Output
Enter an alphabet: u u is a vowel.
The character entered by the user is stored in variable c.
The isLowerCaseVowel evaluates to true if c is a lowercase vowel and false for any other character.
Similarly, isUpperCaseVowel evaluates to true if c is an uppercase vowel and false for any other character.
If both isLowercaseVowel and isUppercaseVowel is true, the character entered is a vowel, if not the character is a consonant.
The isalpha() function checks whether the character entered is an alphabet or not. If it is not, it prints an error message.
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