Write the function prototype for each function described below by writing the function's return type and input parameters list. Do not implement the body of the function. Use the example call to the function to help you write the prototype. To receive full credit, use data types that best describe the function's use and specify input parameters to be pass by reference only when necessary. a) The function display_factors displays the factors of a whole number in either increasing or decreasing order The value 'i' denotes displaying the factors in increasing order and 'd' denotes displaying factors in decreasing order. Here is an example call to the function to display the factors of 12 in increasing order: int main O { cout