Write a complete C++ program that writes the phrase Hello world to the screen. The program does nothing else. Write a complete C++ program that reads in two whole numbers and outputs their sum. Be...

Write a complete C++ program that writes the phrase Hello world to the

screen. The program does nothing else.

Write a complete C++ program that reads in two whole numbers and

outputs their sum. Be sure to prompt for input, echo input, and label all

output.