Write programs that read a line of input as a string and print: a) Only the uppercase letters in the string. b) Every second letter of the string, ignoring other characters such as spaces and symbols....

Write programs that read a line of input as a string and print:

a) Only the uppercase letters in the string.

b) Every second letter of the string, ignoring other characters such as spaces and symbols. For example, if the string is "abc, defg", then the program should print out a c e g.

c) The string, with all vowels replaced by an underscore.

d) The number of vowels in the string.

e) The positions of all vowels in the string.