std::map end() method
- since C++11
- until C++11
// Non const version
iterator end() noexcept;
// Const version
iterator end() const noexcept;
// Const version
const_iterator cend() const noexcept;
// Non const version
iterator end();
// Const version
const_iterator cend();
Returns an iterator
to the element past-the-end of the array. If the array is empty, the returned iterator will be equal tobegin()
.
Attempting to dereference a past-the-end iterator is undefined behaviour
.Parameters
(none)
Return value
Iterator to the first element.
Exceptions
(none)
Complexity
Constant - O(1).
Difference between end and cend
For a const container c
, end and cend are the same - c.end() == c.cend()
For non-const container of type c
they return different iterators:
- Non const container
- Const container
- end
- cend
#include <map>
int main()
{
std::map<int, float> map = { {1, 1.f}, {2, 3.f}, {5, 8.f} };
auto it = arr.end(); // Type: std::map<int, float>::iterator
*std::prev(it) = 5; // ✔ Ok
}
#include <map>
int main()
{
std::map<int, float> map = { {1, 1.f}, {2, 3.f}, {5, 8.f} };
auto it = arr.cend(); // Type: std::map<int, float>::const_iterator
*std::prev(it) = 5; // ❌ Error!
}
- end
- cend
#include <map>
int main()
{
const std::map<int, float> map = { {1, 1.f}, {2, 3.f}, {5, 8.f} };
auto it = arr.end(); // Type: std::map<int, float>::const_iterator
*std::prev(it) = 5; // ❌ Error!
}
#include <map>
int main()
{
const std::map<int, float> map = { {1, 1.f}, {2, 3.f}, {5, 8.f} };
auto it = arr.cend(); // Type: std::map<int, float>::const_iterator
*std::prev(it) = 5; // ❌ Error!
}
Example
Main.cpp
#include <iomanip>
#include <iostream>
#include <map>
#include <string_view>
int main()
{
const std::map<int, std::string_view> coins {
{10, "dime"},
{100, "dollar"},
{50, "half dollar"},
{5, "nickel"},
{1, "penny"},
{25, "quarter"}
}; // initializer entries in name alphabetical order
std::cout << "US coins in circulation, largest to smallest denomination:\n";
for (auto it = coins.crbegin(); it != coins.crend(); ++it) {
std::cout << std::setw(11) << it->second << " = ¢" << it->first << '\n';
}
}
Output
US coins in circulation, largest to smallest denomination:
dollar = ¢100
half dollar = ¢50
quarter = ¢25
dime = ¢10
nickel = ¢5
penny = ¢1
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