programming language is C++

Question 4 Write a program that asks for a sentence to the user and shows this sentence in three different ways: Hint: use functions toupper() and tolower(). a. Everything in lower case b. Everything in upper case c. Altering upper case characters and lowercase characters in the same sentence. For example: "I like potatos" - >IIIKE potAtos Each operation should be handled by a separate function. Please provide 4 test cases at least