Write a program to temporarily store and process student marks for a given test.

Program Specification
This system is designed to temporarily store test marks for a group of students and then produce details including:
the average mark for the group
the top mark for the group
the lowest mark for the group

You are to temporarily store the marks using a Collection called StudentMarks. Initially prompt the user for the subject, number of students and available mark.

Then store the mark achieved against the student name. Once all the entries have been stored display all entries in a list box having produced the percentage mark per student.

Allow the user to erase all the entries and start again with the list of student marks or start at the point of entering a new subject, etc.

Error conditions: No entries are to be blank, no alpha entries in marks