What is Wrong with my program?!?

First thing I would do is clarify whether you want course name and course marks. The way you are doing it is you are entering 10 courses and 10 marks. The way I read it is you need one course, with 10 marks and you calculate the grade from those 10 marks. If I am reading it correct, you can get rid of the mess where you enter 10 courses and 10 marks and use a loop to read through to get the marks.