std::flat_map<Key,T,Compare,KeyContainer,MappedContainer>:: begin, std::flat_map<Key,T,Compare,KeyContainer,MappedContainer>:: cbegin

Returns an iterator to the first element of the flat_map .

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

Parameters

(none)

Return value

Iterator to the first element.

Complexity

Constant.

Example

#include <iostream>
#include <flat_map>
 
int main()
{
    std::flat_map<int, double> map{{4, 4.13}, {9, 9.24}, {1, 1.09}};
 
    for (auto it = map.cbegin(); it != map.cend(); ++it)
        std::cout << '[' << it->first << "] = " << it->second << '\n';
 
    // Unlike std::map's bidirectional iterators, the std::flat_map iterators
    // are random-access, so they can be used with the operator[]:
    auto it = map.cbegin();
    assert(it[0] == map[1]);
    assert(it[1] == map[4]);
    assert(it[2] == map[9]);
}

[1] = 1.09
[4] = 4.13
[9] = 9.24

See also