write an empty main function. write a function called avg eq() that accepts 4 doubles, a, b, c, and d and returns a 1 if the average of a, b and c is greater than d, zero otherwise. write code in main that tests your function with these data: (1,3,5,2) (2,3,4,4) (10,50,25,30) (123,987,42, 300) output (1,3,5,2) -> 1 (2,3,4,4) -> 0 (10,50,25,30) -> 0 (123,987,42,300) -> 1