Pregram-6-Programm 1- Change the code in the posted for the program posted in the same module named "prog" as follows and submit as program 6: Create functions and function prototypes to replace each of the calculator actions. Prototype each function above main and write the function (definition) below main. The input by the user and output statement of each calculation should stay in main and not be moved to a function except the output for function "iseven" which should be done in the function. - Each function will accept the value(s) supplied by the user as parameters and return the result in a return statement (not a printf statement except for "iseven"). - The result returned by each function should be outputted by a printf statement in main. - Create a function named display that contains: menu display statements, the user prompt to select an option, user input. This function should have no parameters and should return a character as the option chosen by the user The functions required are