Why in C++ , we have to start with #include <iostream> ?

Question

Please reply...

Answer 1

It's not mendatoy.
You can also skip it if your program is not doing any standard I/O operations.

or you can just declare them manually in your source file

here is an example 👇
https://code.sololearn.com/cVjeRdabhB4N/?ref=app

Answer 2

Jeff's JK (INACTIVE) It's a library to perform input / output operation.

Answer 3

Thanks for the answer everyone...

Answer 4

Flash you are absolutely right 🙂

I did some research on it and found out that after VS2015 , they moved defination of functions like printf() and scanf() inline into the <stdio.h> and other CRT headers, so now linker can't find their definations if this code is run as it is.
But
It can be resolved if we link "legacy_stdio_definitions.lib" by explicitly giving it as linker input before compiling the code.

That being said the only purpose of this code was to tell OP that "#include<iostream>" need not to be the first line of every C++ program.👍

Answer 5

Just additional answers to I Am Groot ! I Hope these helps.

https://www.sololearn.com/Discuss/105533/i-don-t-know-whether-u-need-include-iostream-is-it-the-beginning-of-any-programm
https://www.sololearn.com/Discuss/84085/why-do-i-need-to-include-iostream-in-order-to-use-cout-even-though-i-use-std-to-access-it-std-cout
https://www.sololearn.com/Discuss/940337/reason-for-the-standard-coding-template-in-c

Answer 6

Arsenic will this run on msvc? .. no! why it works on gcc? because, gcc (linux) links to libc.so by default.

so, i think your solution may not be portable to all compilers.

Answer 7

Without this you cannot use built-in function of input output operations that's why you include this library.

Answer 8

Ohh...Ok...

Answer 9

It includes the declarations of the basic standard input-output library in C++ and it is included because it's functionality is going to be used later on the program. ☺️ 👍 🍓 ⛰️

Answer 10

Have you got the answe now 😄 Jeff's JK 😄