Well it looks like this
https://github.com/S-SHASHANK/Electronic_Store_Management_System/blob/master/main.cpp

Except for the code-projects.org scrawled in the code in various places.
So I'm guessing that's the place you copied it from.

If you look in the parent
https://github.com/S-SHASHANK/Electronic_Store_Management_System
There you'll find a sinlist.h

Does code-projects have the same file?
Or did you miss it in your haste to download your homework?

You apparently chose to ignore the advice given to you in the thread you deleted.

1) What errors are you getting? We are not mind readers.

2) Please post sinlist.h. We can't compile what you have posted without it.

3) You were asked before to use code tags. PLEASE DO SO.
http://www.cplusplus.com/articles/jEywvCM9/
Hint: You can edit your post, highlight your code and press the <> formatting button.
If you're not going to make the slightest bit of effort to make your posts readable, why should we spend the slightest bit of effort helping you?

I asked you to do three things in my post.
You have not done any of them.
If you want help, you are going to have to provide what was asked for.

Well in any case it's not good C++ code. It looks like it was originally C and been 'updated' to be sort of C++ with some classes. It still uses C file handling and some C con-structs. It also uses conio.h and system() etc. IMO I'd consider scrapping this code and starting from scratch with some properly designed/coded C++ code.

As translated from Croatian:

"I came across a lot of such codes
Thank you for the explanation"

Instead of providing what was asked for, OP has deleted his post again.