Check

#include <stdio.h>

int main()
{
    char ch;

    printf("Enter any character: ");
    scanf("%c", &ch);

    if((ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z'))
    {
        printf("\n'%c' is alphabet.\n", ch);
{
        if (ch=='a'||ch=='e'||ch=='i'||ch=='o'||ch=='u' || ch=='A'||ch=='E'||ch=='I'||ch=='O'||ch=='U')
        {
            printf("vowel");
        }
        else
            printf("Consonant");
    }
    }
    else if(ch >= '0' && ch <= '9')
    {
        printf("\n'%c' is digit.\n", ch);
    }
    else
    {
        printf("\n'%c' is special character.\n", ch);
    }

    return 0;
}