How to split code into multiple files
<p>I want to split my code into multiple files. At this moment I have somethink like this but every time I need to include libraries and headers into each of these file.<br>
Is it better way to do this? 
<strong>main.cpp</strong>  </p>

<pre><code>#include &lt;iostream&gt;
#include &lt;stdio.h&gt;
#include &lt;cstdlib&gt;
#include &lt;conio.h&gt;
#include &lt;string.h&gt;
#include &lt;windows.h&gt;
#include "modules/intro.cpp"
#include "modules/login.cpp"

using namespace std;

int main() {
    introModule();
    login();

    system("pause");
}
</code></pre>

<p><strong>intro.cpp</strong>  </p>

<pre><code>#include &lt;iostream&gt;

using namespace std;

    void introModule() {
        // content of intro file
    }
</code></pre>

<p><strong>login.cpp</strong>  </p>

<pre><code>#include &lt;iostream&gt;
#include &lt;conio.h&gt;
#include &lt;string.h&gt;
#include &lt;windows.h&gt;
#include "menu.cpp"

using namespace std;


#define ENTER           13
#define BACKSPACE        8


char passInputCharacter;
char password[20];
const char *accessPassword = "123";

int passInputCharacterPosition = 0;

HANDLE hConsole = GetStdHandle(STD_OUTPUT_HANDLE);

void login() {
    // content of login file
}
</code></pre>