Template:cpp/container/begin/examples/flat multimap

来自cppreference.com
#include <iostream>
#include <flat_map>
 
int main()
{
    std::flat_multimap<int, int> map{{4, 13}, {9, 94}, {1, 19}, {4, 42}};
 
    for (auto it = map.cbegin(); it != map.cend(); ++it)
        std::cout << '[' << it->first << "] = " << it->second << '\n';
 
    // 与 std::multimap 的双向迭代器不同,std::flat_multimap 的迭代器是随机访问的,
    // 可以使用 operator[]:
    auto it = map.cbegin();
    assert(it[1] == 19);
    assert(it[4] == 13);
    assert(it[4] == 42);
    assert(it[9] == 94);
}

输出:

[1] = 19
[4] = 13
[4] = 42
[9] = 94