symbol(s) not found for architecture x86_64 when accessing function in another class

Question

I have a Class named MyClass and I have a function that is defined as public, I'm trying to call this function from another file that has a main function int main(int argc, char *argv[])

MyClass.h:

 class MyClass:
 {
   public:
       MyClass();
       ~MyClass();
       PerformOperation(int*, int);
  }

MyClass.c

void MyClass::PerformOperation(int* myarr, int number)
{
   //Do something
 }

myMainprog.c

int main(int argc, char *argv[])
{
 MyClass obj;
 int* myArr = {1,4,7,0,2};
 int num    = 5;
 obj->(myArr, num);
 }

When I compile my code I get:

Undefined symbols for architecture x86_64:
MyClass::PerformOperation(int* myarr, int number), referenced from: _main in   ccUbOgEv.o
ld: symbol(s) not found for architecture x86_64

I'm running my code on OSX 10.9.4 using g++.

And my problem is not that I did not specify all the files as it is here.

The code works perfectly on linux.