Write a program that has a function that takes two parameters and returns the sum of two parameters. Similarly, write another function that takes two parameters and returns the subtraction result of the first parameter and the second parameter. The third function should take two parameters and return the multiplication result of both parameters. The fourth function should take two parameters, divide the first parameter by the second parameter, and return the result. You should also use a function main where you invoke all four functions. You can use global variables and pass them as arguments to all four functions.