This lab is a review of functions. For this lab you will write a single main program that you will use to test several functions. For each function is it a good idea to first think about exactly what the function is supposed to do and to write the prototype/declaration before trying to write the code for the function. The prototype/declaration for the first function is given for you.

The functions that you should write and test are:

• A function named sum() that returns the sum of two integers that are passed to the function as arguments. The prototype/declaration for the function is:
  int sum(int,int);
• A function named min() that returns the smaller of two integers that are passed to the function as arguments. If both arguments are the same the function should return zero
• A function named circumference() that takes one double as an argument and returns the circumference of a circles with a radius that is equal to the value passed in as an argument. The function should use 3.1417 for PI and that value should be stored as a global constant.
• A function named swap() that swaps the values of two arguments of type double. The arguments should be passed to the function using pass-by-reference.
• A function named swap() that is passed an array of size two and swaps the two values in the array.
• A function named increment() that adds one to every element of an array. The function takes two arguments: an array of integers (the array can be of any size) and a single integer representing the length of the array.

Turn in: Use cscheckin to turn in your program.