What is the function of a control unit?

Write an assembly language program to input a string from the user. your program should do these two things: 1. count and display the number of words in the user input string. 2. flip the case of each character from upper to lower or lower to upper. for example if the user types in: "hello there. how are you? " your output should be: the number of words in the input string is: 5 the output string is : hello there. how are you?