Лямбда-функції

#include <iostream>
#include <vector>
#include <list>
#include <string>
#include <algorithm>
#include <map>

using namespace std;

int main()
{
    list<int> a = { 1, 2, 3, 4, 5 };
    int k = count_if (a.begin(), a.end(),[](int x) { return x % 2 == 0; });
    cout << "1) Even: " << k << endl;

    vector<int> b = { 3, 6, 7, 8, 10 };
    cout << "2) Even: ";
    for_each(b.begin(), b.end(), [](int x){if (x % 2 == 0){cout << x << " ";}});
    cout << endl;

    vector<int> c = { -2, 5, -7, 9, -1 };
    c.erase(remove_if(c.begin(), c.end(), [](int x) { return x < 0; }),c.end());
    cout << "3) Del -n: ";
    for (int i = 0; i < c.size(); i++)
    {
        cout << c[i] << " ";
    }
    cout << endl;

    vector<string> s = { "meet", "sea", "son", "night" };
    char ch = 's';
    int cnt = count_if(s.begin(), s.end(), [ch](string x) { return x[0] == ch; });
    cout << "4) Letter '" << ch << "': " << cnt << endl;


    map<char, int> m;
    for_each(s.begin(), s.end(),[&m](string x) {m[x[0]]++;});
    cout << "5) By letter:" << endl;
    for (auto it = m.begin(); it != m.end(); it++)
    {
        cout << it->first << " - " << it->second << endl;
    }

    return 0;
}