Printing vector of sets in c++

Question

Is there anyway to print a vector of sets easily?

#include <iostream>
#include <set>
#include <vector>

int main ()
{
  std::set<int> myset;
  std::vector<std::set<int> > setVector;
  int myints[] = {5,10,15};
  int elementCount = sizeof(myints) / sizeof(myints[0]);
  myset.insert(myints, myints + elementCount);
  setVector.push_back(myset);
  std::cout << "Elements in vector: " << setVector.size() << " \n";
}

I have added the set to the vector, is there anyway to print it out?

This is just a proof of concept, eventually I will add many more sets to this vector, so ideally I will need to print from the beginning of the vector to the end

Thank you

You have the [range-based for loop](http://en.cppreference.com/w/cpp/language/range-for), you can loop with iterators, loop over the length, use [`std::for_each`](http://en.cppreference.com/w/cpp/algorithm/for_each). — Some programmer dude, Apr 17 '14 at 10:43
See [Pretty Print C++ STL Containers](http://stackoverflow.com/questions/4850473/pretty-print-c-stl-containers). — Mankarse, Apr 17 '14 at 10:45

score 4 · Accepted Answer · edited Apr 17 '14 at 10:54

4

That's quite simple to accomplish using nested range-based loops (introduced by C++11):

for(std::set<int> const &mySet : setVector){
  for(const int i : mySet){
    std::cout << i << " ";
  }
}

Example

edited Apr 17 '14 at 10:54

Alexander

250
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8

answered Apr 17 '14 at 10:47

Constantin

8,721
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1

in C++ 11 you can use auto instead of "std::set const &" – Dmitriy Apr 17 '14 at 11:20
1

@Dmitriy the same things goes for "const int i" – Wes Apr 17 '14 at 11:34

score 1 · Answer 2 · answered Apr 17 '14 at 10:43

1

You can have a look to my (header only) to_string library.

answered Apr 17 '14 at 10:43

Dmitriy

3,305
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score 1 · Answer 3 · answered Apr 17 '14 at 10:52

std::ostream& operator<<(std::ostream& os, const std::set<int>& s) {
    std::copy(s.begin(), s.end(), 
        std::ostream_iterator<int>(os,","));
    return os;
}

template<typename T>
std::ostream& operator<<(std::ostream& os, const std::vector<T>& s) {
    os << "{";
    typename std::vector<T>::const_iterator it = s.begin();
    for( ; it != s.end(); ++it)
        os << *it;

    os << "}";
    return os;
}

Then you can do

std::cout << setVector;

score 1 · Answer 4 · answered Feb 23 '17 at 16:52

1

You can print them directly as :

for(int i=0;i<setVector.size();i++)
{
      for(set<int>::iterator iter=setVector[i].begin();iter!=setVector[i].end();iter++)
}

answered Feb 23 '17 at 16:52

Kartik Madaan

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Printing vector of sets in c++

4 Answers4