Prompt the user for a total grade (double)

According to the syllabus print a letter grade based on the grade entered. For example:

• If the input was 58 the grade displayed will be F
• If the input was 89 the grade displayed will be B+

If the grade was entered was greater than 100, display an error to the user.

If the grade entered was less than 0 display and error to the user

For values 0 <= X <= 100 display the corresponding letter grade.