Compile C++ Code Using The Terminal Directly Without Save File.cpp

I need to compile C++ code directly in the terminal or CLI without saving the file

When is use the below way, It shows me an error.

g++ -x c - <<eof
  #include <iostream>
  using namespace std;

  int main()
  {
    cout << "Hello world";
  }
  eof

>Solution :

You are trying to compile a C++ program using a C compiler.

This works:

g++ '-xc++' - <<eof
#include <iostream>
using namespace std;

int main()
{
    cout << "Hello world";
}
eof