There are five vowel characters {a, e, i, o, u}. If the user given character input is one of them that means it is a vowel otherwise it is a consonant.

Logic

Here we have to manually check the given character with all the vowel characters, we cannot use ASCII value range to determine whether it is a vowel or a consonant. The given character can also be in the form of uppercase.

Program

VovelConsonant.CCopy
#include <stdio.h>

int main() {

    char c;   

    printf("Enter a alphabet : ");
    scanf("%c", &c);

    // if given character is Lower case Vowel or Upper case Vowel
    // then print vowel otherwise consonant
    if ((c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u') 
        || (c == 'A' || c == 'E' || c == 'I' || c == 'O' || c == 'U')) {

        printf("\n%c is a vowel.", c);

    } else{

        printf("\n%c is a consonant.", c);

    }

    return 0;
}
Try It

Output

Enter a alphabet : A
A is a vowel.