Layers implemenation with C or C++

[Eng Heba]

Dears,

Kindly i would like to take your advice on below issue.I'm developing POS applications,The drivers of POS is given to my from POS vendor and all are written in C language.

I'm trying to divide the Work flow into 3 layers

1- Application Layer
2- API
3- C Libraries (Vendor libraries)

1- Application layer

And it should be just customization for each application based on requirement, Just by calling functions in APIs

2- Application programming interface(API)

This is intermediate layer between C libraries provided by vendor and application level . Which isolate higher layer from low level one and it prevents any communication between both. It's flexible layer you can add and function you would like in it

3- C Libraries.

It’s low level layer and it consist of C functions for POS drives

Kindly which is better and why
1- Write Application layer and API layer both in C++
2- Write Application layer in C++ and API in C

Thank you and waiting your urgent reply

Thank you