i know about #include <stdio.h> header file ,is we can replace with <iostream> header file with < stdio.h > ??

Answer 1

I don't understand your question clearly,
there may be 2 possible answers to your question in 2 different manner.

First,
no you can't because both are different headers and have different function, and objects defined inside them, if your are saying you will use stdio.h and want to use cout, cin, endl.. etc.., then sorry buddy, then you have you define there terms explicitly.
so in short no you can't

second.
yes, in a manner you can say, but then you can't use any of the object/function defined under iostream, you have to use whatever is defined in stdio.h,
have to use printf , scanf ,..

On a overview still my answer is no you can't, they both possess different properties.

Answer 2

You are really just asking this.

https://www.sololearn.com/discuss/28793/?ref=app
https://www.sololearn.com/discuss/1312598/?ref=app

Answer 3

Ty for clarification

Answer 4

Hay...