Q2. (40 marks) Write a C++ program that asks the user to enter two positive integer numbers as the lower bound and upper bound. Then it asks the user to enter a character: -If the entered character is 'a', function 1 is called. -If the entered character is 'b', function is called and then the value of result variable is printed -If the entered character is 'c', function 3 is called and the returned value of the function 3 is printed -If the user enters any other character, the program prints "invalid input" and terminates. Function 1: I This function accepts the upper bound and lower bound numbers as the input arguments and prints out all the numbers in this range (Inclusive) which are multiples of both 7 and 2. Function 2: This function has no return value. It accepts 3 input arguments: the upper bound and lower bound numbers and a variable result (by reference) and calculates the difference between two entered numbers and save it in the result Function 3: This function returns a variable of type double (sum) and accepts the upper bound and lower bound numbers (lower and upper variables) as input arguments. It calculates the results of following equation and returns the sum variable. (please note that the number of digits after the decimal point should be set to 3 for the sum value) 1 sum 1 lower lower: 1 lewer.2 PPT