# std::multimap<Key,T,Compare,Allocator>::begin, std::multimap<Key,T,Compare,Allocator>::cbegin

From cppreference.com
< cpp‎ | container‎ | multimap

iterator begin(); | (1) | (noexcept since C++11)
const_iterator begin() const; | (2) | (noexcept since C++11)
const_iterator cbegin() const noexcept; | (3) | (since C++11)

Returns an iterator to the first element of the `multimap`.

If the `multimap` is empty, the returned iterator will be equal to end().

### Parameters

(none)

### Return value

Iterator to the first element.

### Complexity

Constant.

### Notes

libc++ backports `cbegin()` to C++98 mode.

### Example

Run this code

    #include <algorithm>
    #include <cassert>
    #include <cstddef>
    #include <iostream>
    #include <map>
    #include <string>

    int main()
    {
        auto show_node = [](const auto& node, char ending = '\n')
        {
            std::cout << "{ " << node.first << ", " << node.second << " }" << ending;
        };

        std::multimap<std::size_t, std::string> mmap;
        assert(mmap.begin() == mmap.end());   // OK
        assert(mmap.cbegin() == mmap.cend()); // OK

        mmap.insert({ sizeof(long), "LONG" });
        show_node(*(mmap.cbegin()));
        assert(mmap.begin() != mmap.end());   // OK
        assert(mmap.cbegin() != mmap.cend()); // OK
        mmap.begin()->second = "long";
        show_node(*(mmap.cbegin()));

        mmap.insert({ sizeof(int), "int" });
        show_node(*mmap.cbegin());

        mmap.insert({ sizeof(short), "short" });
        show_node(*mmap.cbegin());

        mmap.insert({ sizeof(char), "char" });
        show_node(*mmap.cbegin());

        mmap.insert({{ sizeof(float), "float" }, { sizeof(double), "double"}});

        std::cout << "mmap = { ";
        std::for_each(mmap.cbegin(), mmap.cend(), [&](const auto& n) { show_node(n, ' '); });
        std::cout << "};\n";
    }

Possible output:

    { 8, LONG }
    { 8, long }
    { 4, int }
    { 2, short }
    { 1, char }
    mmap = { { 1, char } { 2, short } { 4, int } { 4, float } { 8, long } { 8, double } };

### See also

endcend (C++11) | returns an iterator to the end (public member function)
begincbegin (C++11)(C++14) | returns an iterator to the beginning of a container or array (function template)

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