Might be 3 different skills here:
1) learn c++ 2) learn deep learning 3) learn c++ with deep learning: much easier once you have done 1) and 2)
1) learn c++ 2) learn deep learning 3) learn c++ with deep learning: much easier once you have done 1) and 2)
So I believe you should more strongly recommend 1) and 2) and include what a later poster added about various frameworks: "BLAS, LAPACK, and maybe the whole CUDA family (CUDA, cuBLAS, cuDNN, etc)", see @madenine.
Hmmm... It seems not possible to search for "The C++ programming language" on amazon. As fast as I type '++' Amazon deletes the characters. >:( Luckily a search for "The C Programming language" also lists the 4th edition of Stroustrups book. ... And after searching via Google, the Amazon page now works. Weird!