Can I use bits/stdc++.h instead iostream?

Question

It means it includes all standard bits and standart c++ library

Answer 1

I believe you can but I think that it is a bad habit and can lead to issues. It appears to have more disadvantages than advantages.

Here are some resources for more detailed information on this topic:
https://stackoverflow.com/questions/31816095/why-should-i-not-include-bits-stdc-h
https://stackoverflow.com/questions/25311011/how-does-include-bits-stdc-h-work-in-c/25311052#25311052
https://www.geeksforgeeks.org/bitsstdc-h-c/

Answer 2

In C language when I write system ("pause"); it works. But when I write it into C++ in it gives error. In compiler says undeclared function etc.