Problem 18
Write a program that counts the total number of vowels in a sentence. Output the frequency of each vowel.
Problem 19
Write a program that inserts the characters "******" in the exact middle of a string.
Problem 20
Write a program that erases the sequences "by" and "BY" from a string.
Problem 21
Write a program that inputs a line of text, replaces all punctuation marks with spaces and uses the C-string library function strtok to tokenize the string into individual words.
Problem 22
Write a program that inputs a line of text and prints the text backwards. Use iterators in your solution.
Problem 25
a bcb cdedc defgfed efghihgfe fghijkjihgf ghijklmlkjihg hijklmnonmlkjih ijklmnopqponmlkji jklmnopqrsrqponmlkj klmnopqrstutsrqponmlk lmnopqrstuvwvutsrqponml mnopqrstuvwxyxwvutsrqponm nopqrstuvwxyz{zyxwvutsrqpon
Problem 28
Modify class Employee in Figs. 13.613.7 by adding a private utility function called isValidSocialSecurityNumber. This member function should validate the format of a social security number (e.g., #--, where # is a digit). If the format is valid, return true; otherwise return false.
