Problem
Java program that:
Prompt the user for his or her first name
Print a message saying hello to the user
Tell the user how many characters are in his or her name
Ask the user for the year of his or her birth
Calculate and print the age the user will be this year
Declare a constant for average life expectancy; set its value to 78.94
Print a message that tells the user the percentage of his or her expected life lived so far formatted to one decimal place
Generate a random number between 1 and 20
Output a message telling the user that the program is thinking of a number between 1 and 20 and ask for a guess
Output a message telling the user the number and how far away from the number the user's guess was.