Following code is legal for C++14 compiler
// g++ -std=c++14 -pedantic -pthread main.cpp
// output: 1 2 3 4 5 1 1 1
#include <algorithm>
#include <vector>
#include <functional>
#include <iterator>
#include <iostream>
int main()
{
std::vector<int> a = { 1, 2, 3, 2, 4, 5, 1, 1, 3, 5, 1, 5 }, b = { 2, 5, 5, 3 }, c;
std::copy_if(a.begin(), a.end(), std::back_inserter(c),
std::bind(std::less<>(), // this won't work in pre-C++14
std::bind(
std::count<std::vector<int>::iterator, int>,
std::bind(static_cast<std::vector<int>::iterator (std::vector<int>::*)()>(&std::vector<int>::begin), &c),
std::bind(static_cast<std::vector<int>::iterator (std::vector<int>::*)()>(&std::vector<int>::end), &c),
std::placeholders::_1
),
std::bind(
std::minus<>(), // this won't work in pre-C++14
std::bind(
std::count<std::vector<int>::iterator, int>,
a.begin(),
a.end(),
std::placeholders::_1
),
std::bind(
std::count<std::vector<int>::iterator, int>,
b.begin(),
b.end(),
std::placeholders::_1
)
)
)
);
std::copy(c.begin(), c.end(), std::ostream_iterator<int>(std::cout, " "));
std::cout << std::endl;
}
It is meant to create vector c from elements of vector a , excluding those that match count and value of elements in vector b. E.g. if a contains three 2 and b - two of them, only one 2 would be present in c.
a) how possible to adapt this code for C++11? Intuitive leap that less<> and minus<> parameter would be ...::difference_type didn't work, compiler messages aren't helpful either
b) current version removes last matches sequence-wise. What code would remove first matches?
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