Why we put .h in it <iostream.h>

Question

i mean that why we put .h in < iostream.h>

Answer 1

At least for my compiler, you don't actually need the '.h'; you can just use <iostream>

Answer 2

iostream.h is deprecated by those compilers that provide it, iostream is part of the C++ standard.
Anyway <iostream.h> is old and some compilers does not support it

Answer 3

it isn't necessary

Answer 4

.h is for C

Answer 5

it's a library function. with out it you can't run your program