Simple C++ program design, just need to modify the complete Cpp file, top-down design

 1. Only using the library <iostream>,<fstream>,<iomanip>,<cstblib>,<cmanth> 

2. You can just edit my cpp file below! It works perfectly, but it is not top-down design.  All you need to do is, making function call in the main function, so the body will look like clearly and simply.

3. You also can use chegg.com and copy the question to get more help!

 4. Please! If you have any question, let me know ASAP！