$1.$ Write the following member functions for the class arrayListType. The class definition for arrayListType is in the notes, the book, and in this Module. a$.$ int sum $()-$ returns the sum of all the elements in the list.b$.$ double average$()-$ calculates and returns the average of the elements in the list.c$.$ int higherThan$($int$)-$ returns the first number in the list that is greater than the argument passed to the function. If it does not find a number greater than the argument, then it prints a message and returns $-1000.$d$.$ bool firstIsLast$()$ returns true if the first number in the list is the same as the last number in the list.e$.$ void add$6()$ adds $6$ to each number in the list. The function does not print anything, return anything. It just adds $6$ to each number in the list.Remember these are all member functions of the class arrayListType.