C++ programming function help

I'm having some trouble trying to program these problems and putting them into the main function. Please help me by giving some advice or website that offer good information for me.
1. Write a function that accepts a string of characters from a user and displays the string one word per line.
2. Write a function that accepts a string of characters, then output all the characters of the string in a reversed order.
3. Write a function that counts the number of words in a string. A word is encountered whenever a transition from a blank space to a nonblank character is encountered. Assume that the string contains only words separated by blank spaces.
4.Write a function that accepts a string from a user and convert all lower case letters to upper case letters and also eliminates all blank spaces in the string.

Write a program that tests all the above functions.