Write a program with three functions: upper, lower, and reverse. The upper function should accept C-string as an argument. It should step through all the characters in the string, converting each to uppercase. The lower function, too, should accept a pointer to a C-string as an argument. It should step through all the characters in the string, converting each to lowercase. Like upper and lower, reverse should also accept a C-string. As it steps through the string, it should test each character to determine whether it is upper or lowercase, it should be converted to lowercase. If a character is lowercase, it should be converted to uppercase.

Test the functions by asking for a string in function main, then passing it to them in the following order: reverse, lower, and upper.