vowel function definition

use:
/* return the number of times vowel occurs in the string. */
long dystring::countVowel(void)

/* return the number of lower case vowels in the string. */
long dystring::countVowelLowerCase(void)

/* return the number of upper case vowels in the string. */
long dystring::countVowelUpperCase(void)
vowel functions prototype

long countVowel(void);  //return the number of vowels in the string.
long countVowelLowerCase(void);  //return the number of lower case
vowels in the string.
long countVowelUpperCase(void);  //return the number of upper case
vowels in the string.