Exercise4: Write a complete C++ program that gets quiz, midterm and final marks from the user. Then, calculate the average and display the result to user by using the following user defined functions. (Quiz: 20%, Midterm: 30%, Final: 50% ) Function 1: double quizPercentage(int quiz); Function2: double midtermPercentage(int midterm); Function3: double finalPercentage(int final); Function4: void calcAverage(double quiz, double midterm, double final)