Toupper and tolower (pages 470-471)

Function toupper has one input which is a character (let's call it ch). If 
ch is lowercase, the function returns the ASCII position of the uppercase 
version of ch. If ch is not lowercase, the function returns the ASCII 
position of ch itself.

Function tolower has one input which is a character (let's call it ch). If 
ch is uppercase, the function returns the ASCII position of the lowercase 
version of ch. If ch is not uppercase, the function returns the ASCII 
position of ch itself.

Example: See the solution of Question 6 on Lab 3.