Exam #2 programming problems

I strongly suggest that each student develop a C++ solution to the following problems in preparation for the coding portion of the first exam. While I do not promise that the practical part of the exam will be *exactly* the same as any one of these problems, the actual test question will at least be very similar to one or more of these practice problems.

1. Write a program which requests from the user a student's semester average. The program should display the letter grade the student earned for the semester.
   
   You must write two functions:
   
      int getSemesterAverage()
      char assignLetterGrade(int score)
   
   Be sure to declare appropriate constants.
   
   
   Sample Output
   Here is a screenshot of my code running.
   
   
   Letter Lookup output



2. Write a program that counts how many times the lowercase letter 'e' appears in a user-input string.
   
   You must write one function:
   
      int eCount(string input)
   
   
   Sample Output
   Here is a screenshot of my code running.
   
   
   e Count output



3. Write a program that calculates
   
   
   
   if x is strictly greater than y,
   
   
   
   if y is strictly greater than x, and
   
   
   
   if x is exactly equal to y.
   
   You must write one function:
   
      void blackBox(int x, int y)
   
   
   Sample Output
   Here is a screenshot of my code running.
   
   
   Mystery Math output



4. Write a program that requests the subtotal of a restaurant bill and the percentage the diner would like to tip. The program calculates the tip and the final total.
   
   You must write one function:
   
      void calculateTotal(double bill, double rate, double &tip, double &total)
   
   
   Sample Output
   Here is a screenshot of my code running.
   
   
   Tip Calculator output