#include <iostream>

class ClassA
{
  public:
    int a, b;

    void add();

};

void ClassA::add()
{

//    printf("sdf");
}

#import "ViewController.h"
#import "ClassA.cpp"
- (void)viewDidLoad
{
    ClassA a;
    a.add();



    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
}

-cclib -lstdc++

#include <iostream>

class ClassA
{
  public:
    int a, b;

    void add();

};

#include "ClassA.h"
void ClassA::add()
{

//    printf("sdf");


}

#import "ClassA.h"
... the rest of the file ...