g++ -c hasArray.cpp
g++ -c Main.cpp
g++ Main.o hasArray.o -o output

Undefined symbols for architecture x86_64:
  "hasArray::passPointer()", referenced from:
      _main in Main.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

#include <stdio.h>
#include <iostream>
#include "hasArray.hpp"

using namespace std;

int * passPointer(){
    cout << "Inside hasArrayn";
    int array[5] = {1,2,3,4,5};
    int * pointer = &array[0];

    cout << "Array: ";
    for( int i =0 ; i < 3; i++)
        cout << array[i] << ", ";
    cout << "n";
    cout << "Pointer: " << pointer;
    return pointer;
}

#ifndef _HASARRAY_H_
#define _HASARRAY_H_

#include <stdio.h>
#include <iostream>

class hasArray{

public:
    //    hasArray();
    int * passPointer();
};

#endif

#include <stdio.h>
#include <iostream>
#include "hasArray.hpp"

using namespace std;

int main(){
    cout << "Inside mainn";
    hasArray x;
    int * pointer = x.passPointer();
    cout << "Pointer: " << pointer << "n";
    cout << "Array: ";
    for( int i =0 ; i < 3; i++)
        cout << pointer[i] << ", ";
    return 0;
}