In C++, am I paying for what I am not eating?

So, in this case, what am I paying for?

std::cout is more powerful and complicated than printf. It supports things like locales, stateful formatting flags, and more.

If you don't need those, use std::printf or std::puts - they're available in <cstdio>.

It is famous that in C++ you pay for what you eat.

I also want to make it clear that C++ != The C++ Standard Library. The Standard Library is supposed to be general-purpose and "fast enough", but it will often be slower than a specialized implementation of what you need.

On the other hand, the C++ language strives to make it possible to write code without paying unnecessary extra hidden costs (e.g. opt-in virtual, no garbage collection).

You are not comparing C and C++. You are comparing printf and std::cout, which are capable of different things (locales, stateful formatting, etc).

Try to use the following code for comparison. Godbolt generates the same assembly for both files (tested with gcc 8.2, -O3).

main.c:

#include <stdio.h>

int main()
{
    int arr[6] = {1, 2, 3, 4, 5, 6};
    for (int i = 0; i < 6; ++i)
    {
        printf("%d\n", arr[i]);
    }
    return 0;
}

main.cpp:

#include <array>
#include <cstdio>

int main()
{
    std::array<int, 6> arr {1, 2, 3, 4, 5, 6};
    for (auto x : arr)
    {
        std::printf("%d\n", x);
    }
}