2. Given the code below, write an if structure to display the maximum number among x, y, and z. (30%) double x, y, z; cin >> x >> y >> z; 3. Write a function to compute the average of all elements of a double array. The function should take 2 parameters: the array and the size of the array. The function should return the average of all elements. You may use a for loop in your function. (40%)