Exercise 1: Write a complete program to read a string of
characters from the standard input and insert them in the stack.
Print the size of the stack when you are done after the stack is
filled out. Then, print out to the screen all the vowels in
reverse order. Use classes and functions to do the above
program. Exercise 2: Write a program that takes marks of 10
students and store them in the stack then take out these from
the stack and print the average of all the marks of 10 students.
Hint : make sure that every time you do a push operation you
should check if the stack is not full and in pop operation you
should check if the stack is not empty.