#include <algorithm>
#include <cassert>
#include <functional>
#include <iostream>
#include <iterator>
#include <set>
#include <string>
#include <vector>
#include <memory>
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Weffc++"
#pragma GCC diagnostic ignored "-Wunused-local-typedefs"
#include <boost/shared_ptr.hpp>
#pragma GCC diagnostic pop
struct MyClass
{
MyClass(const std::string& s, const int x) : m_s(s), m_x(x) {}
const std::string m_s;
const int m_x;
};
bool operator<(const MyClass& lhs, const MyClass& rhs) = delete;
//Prevent ordering sets by the pointers their addresses
bool operator<(const boost::shared_ptr< MyClass> lhs, const boost::shared_ptr< MyClass> rhs) = delete;
bool operator<(const boost::shared_ptr< MyClass> lhs, const boost::shared_ptr<const MyClass> rhs) = delete;
bool operator<(const boost::shared_ptr<const MyClass> lhs, const boost::shared_ptr< MyClass> rhs) = delete;
bool operator<(const boost::shared_ptr<const MyClass> lhs, const boost::shared_ptr<const MyClass> rhs) = delete;
//Display x first
std::ostream& operator<<(std::ostream& os, const MyClass& m)
{
os << m.m_x << ' ' << m.m_s;
return os;
}
struct MySuperClass
{
MySuperClass(const std::string& s, const int x)
: m_c(boost::shared_ptr<MyClass>(new MyClass(s,x))) {}
const boost::shared_ptr<MyClass> m_c;
};
int main()
{
//Put MySuperClass instances in std::vector
std::vector<MySuperClass> v;
v.push_back(MySuperClass("five",5));
v.push_back(MySuperClass("four",4));
v.push_back(MySuperClass("one",1));
v.push_back(MySuperClass("six",6));
v.push_back(MySuperClass("three",3));
v.push_back(MySuperClass("two",2));
//Create a std::set with a custom MyClass ordering
std::set<boost::shared_ptr<MyClass>,std::function<bool(boost::shared_ptr<MyClass>,boost::shared_ptr<MyClass>)>> s(
[](const boost::shared_ptr<MyClass> lhs, const boost::shared_ptr<MyClass> rhs)
{
return lhs->m_x < rhs->m_x;
}
);
//Insert MyClass instances in std::map by extracting these from std::vector
std::transform(v.begin(),v.end(),std::inserter(s,s.begin()),
[](const MySuperClass& c)
{
return c.m_c;
}
);
//Show that the set orders by MyClass their x
std::transform(s.begin(),s.end(),std::ostream_iterator<MyClass>(std::cout,"\n"),
[](const boost::shared_ptr<MyClass> m) { return *m; }
);
}
/* Screen output:
1 one
2 two
3 three
4 four
5 five
6 six
Press <RETURN> to close this window...
*/
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