Chapter 2, Problem 15P

Develop a well-structured function procedure that is passed a numeric grade from 0 to 100 and returns a letter grade according to the scheme:

Letter	Criteria
A	$90\le \text{ numeric grade}\le 100$
B	$80\le \text{ numeric grade}<90$
C	$70\le \text{ numeric grade}<80$
D	$60\le \text{ numeric grade}<70$
F	$\text{numeric grade}<60$