ex12_10.cpp

/***************************************************************************
*  @file       The code is for the exercises in C++ Primmer 5th Edition
*  @author     Yue Wang
*  @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 <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;
}