Why is my output buffer getting flushed in C++?

For what i know, the differences between this codes:

#include <iostream>
//CODE 1
int main(){
    std::cout << "Hi there" << std::endl;
    while(1);
    return 0;
}

#include <iostream>
//CODE 2
int main(){
    std::cout << "Hi there \n";
    while(1);
    return 0;
}

Is that, in the 'CODE 1', the endl introduces a newline, but also flushes the output buffer (cout), so, whenever the 'cout' statement gets executed, i will have 'Hi there' printed on the terminal

But, for what i know, in the 'CODE 2', when i have a newline '\n', i dont have a flush in the output buffer, and this output buffer flushing happens whenever i have a 'cin' statement or the program finish its execution, so, why both codes flushes the output buffer (i mean both codes print the messages "Hi there") if only the code 1 shoould do it

Is this a GNU/GCC thing? so if i change to a C++ standard, now, only code 1 should print the message right?

Thanks in advance!