To check vowel or constant

#include <stdio.h>

int main()
{
    char c;
    int vowel;
    printf("Enter the alphabet to check : ");
    scanf("%c",&c);
    vowel = (c=='a'||c=='e'||c=='i'||c=='o'||c=='u'||c=='A'||c=='E'||c=='I'||c=='O'||c=='U');
    
    if (vowel) 
    {
        printf("%c is a vowel",c);
    }
    else
    {
        printf("%c is a constant",c);
    }
    return 0;
}