issue with vector-addion.cu

[dsinsight]

Hey Nick,
I am getting an error in / Boundary Check
if (tid < N) c[tid] = a[tid] + b[tid];
but when i corrected according to vs suggestion to / Boundary Check
if (tid < N) c[tid] == a[tid] + b[tid];
then it says warning #174-D: expression has no effect
1> if (tid < N) c[tid] == a[tid] + b[tid];
However, after this warning, it showed "completed successfully" .
I used the VS-2022 community. Can you please explain what happened, I am still confused

Also, when I compile the same program with nvcc on WSL2-ubuntu 20.2 it says
vector-add.cu(26): warning #174-D: expression has no effect
but the compilation was done and on running the output file give this -
vector-add: vector-add.cu:33: void verify_result(std::vector&, std::vector&, std::vector&): Assertion `c[i] == a[i] + b[i]' failed.
Aborted

Can you please help me out with the same

Regards
Pronod