“std_lib_facilities.h” showing error

Question

I am using Codeblocks 17.12 and have already set compiler settings to C++11 standard. I am studying from Bjarne Stroustrup\'s book \"Programming - Principles and Practice us

Answer 1

we should not use this file "std_lib_facilities.h" at all as it is using deprecated or antiquated headers.

You should #include standard headers as you use them. The std_lib_facilities.h might get out of sync.

#include
#include "std_lib_facilities.h"
int main() {
    std::cout<<"Hello world";
}

should rather be

#include
// #include "std_lib_facilities.h" Remove this entirely!
int main() {
    std::cout<<"Hello world";
}

Using more standard features like std::string should be:

#include
#include
int main() {
    std::string hello = "Hello world";
    std::cout<

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Extending further, reading the #include std_lib_facilities.h in your books example should probably become to expand the actually necessary standard header includes for your compilable and productive code.
Here's just a default starting template as used by Coliru

#include 
#include 

template
std::ostream& operator<<(std::ostream& os, const std::vector& vec)
{
    for (auto& el : vec)
    {
        os << el << ' ';
    }
    return os;
}

int main()
{
    std::vector vec = {
        "Hello", "from", "GCC", __VERSION__, "!" 
    };
    std::cout << vec << std::endl;
}

Sure you could gather up the

#include 
#include 

in a separate header file, but that would be tedious to keep in sync of what you need in particular with all of your translation units.

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Another related Q&A:

Why should I not #include ?