Well in computers we use iostream.h in turbo c++ but in cpp droid app there is only iostream used why that is

Answer 1

Turbo c++ is old and was published before c++ was standardised.

From Wikipedia:

Before the initial standardization in 1998, C++ was developed by Bjarne Stroustrup at Bell Labs since 1979, as an extension of the C language as he wanted an efficient and flexible language similar to C, which also provided high-level features for program organization.

https://www.quora.com/What-does-h-stand-for-in-iostream-h

https://softwareengineering.stackexchange.com/questions/127023/why-is-include-iostream-h-bad

Answer 2

iostream.h is outdated