How to use remove_if

albert.cc

#include <iostream>
#include <vector>
#include <algorithm>

using std::vector;
using std::remove_if;
using std::cout;
using std::endl;

bool smol(vector<int> vec);

int main()
{
  auto myvec = vector<vector<int>>{};
  myvec.push_back(vector<int> { 1, 2, 3 });
  myvec.push_back(vector<int> { 4, 5 });
  myvec.push_back(vector<int> { 6 });
  myvec.push_back(vector<int> { 7, 8, 9 });
  myvec.push_back(vector<int> { 10 });

  cout << "before remove_if:" << endl;

  for (auto inner : myvec) {
    for (auto i : inner) {
      cout << i  << " ";
    }
    cout << endl;
  }

  myvec.erase(remove_if(myvec.begin(), myvec.end(), smol), myvec.end());

  cout << "after remove_if:" << endl;

  for (auto inner : myvec) {
    for (auto i : inner) {
      cout << i  << " ";
    }
    cout << endl;
  }
}

bool smol(vector<int> vec)
{
  return vec.size() < 2;
}

/* OUTPUT
 [fg-386] albert > g++ --std=c++11 albert.cc
 [fg-386] albert > ./a.out
before remove_if:
1 2 3
4 5
6
7 8 9
10
after remove_if:
1 2 3
4 5
7 8 9
*/