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@arjun-menon
Created December 29, 2016 07:18
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#include <set>
#include <string>
#include <memory>
#include <iostream>
#include <functional>
template< typename T >
struct shared_ptr_comparator {
bool operator()(const std::shared_ptr<T> &a, const std::shared_ptr<T> &b) const {
return std::less<T>()(*a, *b);
}
};
void ptr_set_with_custom_comparator() {
std::set< std::shared_ptr<std::string>, shared_ptr_comparator<std::string> > ptr_set;
ptr_set.insert(std::make_shared<std::string>("world"));
ptr_set.insert(std::make_shared<std::string>("hello"));
ptr_set.insert(std::make_shared<std::string>("abc"));
for(auto const& entry : ptr_set) {
std::cout << *entry << std::endl;
}
}
void ptr_set_with_owner_less() {
std::set< std::shared_ptr<std::string>, std::owner_less<std::shared_ptr<std::string>> > ptr_set;
ptr_set.insert(std::make_shared<std::string>("world"));
ptr_set.insert(std::make_shared<std::string>("hello"));
ptr_set.insert(std::make_shared<std::string>("abc"));
for(auto const& entry : ptr_set) {
std::cout << *entry << std::endl;
}
}
void raw_set() {
std::set<std::string> raw_set;
raw_set.insert("world");
raw_set.insert("hello");
raw_set.insert("abc");
for(auto const& entry : raw_set) {
std::cout << entry << std::endl;
}
}
int main() {
std::cout << "A basic set of strings:" << std::endl;
raw_set();
std::cout << std::endl;
std::cout << "A set of shared_ptr<string>s with owner_less as the comparator:" << std::endl;
ptr_set_with_owner_less();
std::cout << std::endl;
std::cout << "A set of shared_ptr<string>s with the comparator shared_ptr_comparator:" << std::endl;
ptr_set_with_custom_comparator();
return 0;
}
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