Write a program with three functions: upper, lower, and reverse.
The upper function will accept a pointer to a string or C-string as an argument. It will step through each character in the string converting it (where necessary) to uppercase.
The lower function will accept a pointer to a string or C-string as an argument. It will step through each character in the string converting it (where necessary) to lowercase.
Like the upper and lower functions, the reverse function will accept a pointer to a string or C-string. It will step through each character in the string converting uppercase characters to lowercase and lowercase characters to uppercase; numbers and special characters will be unaffected.
The program will execute the functions in the following order: upper, lower, and reverse.