himake: hello.o printing.o name.o
    g++ -o himake hello.o printing.o name.o

hello.o: hello.cpp
    g++ -c hello.cpp

printing.o: printing.cpp
    g++ -c printing.cpp

name.o: name.cpp
    g++ -c name.cpp

// hello.cpp

// standard library
#include <iostream>
#include <string>
using namespace std;

// user defined header files
#include "name.h"
#include "printing.h"

int main ()
{
    string name;

    name = getName();   // getName is in name.h
    printHello(name);  // printHello is in print.h

    return 0;
}

// printing.cpp

// user defined include files
#include "printing.h"

void printGreeting(void)
{
    cout << "Your name: ";
    return;
}

void printHi (string  name)
{
    cout <<  "Hi, " << name << endl;
    return;
}

// name.h

#include <iostream>
using namespace std;

string getName();

// printing.cpp

// user defined include files
#include "printing.h"

void printGreeting(void)
{
    cout << "Your name: ";
    return;
}

void printHi (string  name)
{
    cout <<  "Hi, " << name << endl;
    return;
}

// printing.h

#include <iostream>
using namespace std;

void printGreeting();
void printHello(string);