#include <iostream>
#include <algorithm>
#include <list>
 
class Foo
{
    int _m;
public:
    Foo(int m): _m(m){}
    friend bool operator==(const Foo& lhs, const Foo& rhs);
};
 
bool operator==(const Foo& lhs, const Foo& rhs)
{
    return lhs._m == rhs._m;
}
 
int main() 
{
    Foo foo1{42};
    Foo foo2{24};
 
    std::list<Foo> lst;
    lst.push_back(foo1);
    lst.push_back(foo2);
    auto it = std::find(lst.begin(), lst.end(), foo1);
    if(it != lst.end())
        std::cout << "Found!" << std::endl;
    else
        std::cout << "Not found!" << std::endl;
}
 

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