What is the use of including string library because we can use its function without including it ?

Question

For example ;
#include <iostream >
#include <string>
using namespace std;
int main (){

string a = 'sudip';
cout <<a.length ();

return 0;
}

NEXT PROGRAM:

#include <iostream >
using namespace std;
int main (){

string a = 'sudip';
cout <<a.length ();

return 0;
}

Both programs gives output without any error.

Answer 1

I asked the same question before

https://www.sololearn.com/post/69831/?ref=app

Answer 2

The iostream library already has the string library included. It's not necessary to include <string> when <iostream> is in your code.