ex12_10.cpp

/***************************************************************************
 *  @file       The code is for the exercises in C++ Primmer 5th Edition
 *  @author     Alan.W
 *  @date       23  DEC 2013
 *  @remark
 ***************************************************************************/
//!
//! Exercise 12.10:
//! Explain whether the following call to the process function defined on page
//! 464 is correct. If not, how would you correct the call?
//  correct.

#include <iostream>
#include <vector>
#include <string>
#include <memory>

void process(std::shared_ptr<int> ptr)
{
    std::cout << "inside the process function:" << ptr.use_count() << "\n";
}

int main()
{
    std::shared_ptr<int> p(new int(42));
    process(std::shared_ptr<int>(p));

    /**
      * codes below shows how the reference count change.
      */
    std::cout << p.use_count() << "\n";
    auto q = p;
    std::cout << p.use_count() << "\n";
    std::cout << "the int p now points to is:" << *p << "\n";
    return 0;
}