returning a reference to a set in c++

Asked Nov 05 '16 at 14:15

Active Nov 05 '16 at 14:18

Viewed 15 times

In this case is it worthwhile to consider that the method "merge" should return a reference on a set instead of a copy of a set. In the case of I want to return a reference on a set how should I handle the case ?

#include <iostream>
#include <set>

using namespace std;

class T {
public:
    set<int> merge();
private:
    set<int> a = {1, 2, 3};
    set<int> b = {4, 5, 6};
};

set<int>
T::merge()
{
    set<int> merged;
    merged.insert(a.begin(), a.end());
    merged.insert(b.begin(), b.end());
    return merged;
}

int main(int argc, const char * argv[]) {
    T test;
    auto r = test.merge();
    for(auto e: r)
       cout << e << endl;
    return 0;
}

edited Nov 05 '16 at 14:18

asked Nov 05 '16 at 14:15

vgauthier

You shouldn't return references to local variables. What you could do is pass an argument to your merge method and insert both a and b there. – Pedro Boechat Nov 05 '16 at 14:18
@PedroBoechat I was going to suggest that but I like the idea of a return value. Isn't there some magical C++11 construct to be able to do such a thing? Damn my C++ needs dusting. – Jean-François Fabre Nov 05 '16 at 14:22
Add a argument to merge method and then pass it by ref . – Cherkesgiller Nov 05 '16 at 14:29

returning a reference to a set in c++

0 Answers0