C++ multimap::cend() Function

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The C++ std::multimap::cend() function is used to return a constant iterator to the element following the last element of the multimap. This iterator is used for read-only access, ensuring that the elements are not modified. It is often utilized in conjunction with cbegin() to iterate through the multimap from start to end in a read-only manner. The time complexity of this function is constant i.e.O(1).

Syntax

Following is the syntax for std::multimap::cend() function.

const_iterator cend() const noexcept;

Parameters

This function does not accept any parameter

Return value

This function returns a constant iterator pointing to the last element of the multimap.

Example

Let's look at the following example, where we are going to demonstrate the usage of cend() function.

#include <iostream>
#include <map>
int main()
{
    std::multimap<int, std::string> x = {{1, "Hi"}, {2, "Hello"}, {2, "Namaste"}, {3, "Vanakam"}};
    for (auto a = x.cbegin(); a != x.cend(); ++a) {
        std::cout << a->first << ": " << a->second << std::endl;
    }
    return 0;
}

Output

Output of the above code is as follows −

1: Hi
2: Hello
2: Namaste
3: Vanakam

Example

Consider the another scenario, where we are going to perform the reverse iteration using cend() function.

#include <iostream>
#include <map>
int main()
{
    std::multimap<int, std::string> a = {{1, "Tutorix"}, {2, "TP"}, {2, "TutorialsPoint"}, {3, "Welcome"}};
    for (auto x = std::make_reverse_iterator(a.cend()); x != std::make_reverse_iterator(a.cbegin()); ++x) {
        std::cout << x->first << ": " << x->second << std::endl;
    }
    return 0;
}

Output

Following is the output of the above code −

3: Welcome
2: TutorialsPoint
2: TP
1: Tutorix

Example

In the following example, we are going to find all the elements with a specific key and iterate over that range using cend() function.

#include <iostream>
#include <map>
int main()
{
    std::multimap<int, std::string> x = {{1, "Audi"}, {2, "Cruze"}, {2, "Sail"}, {3, "BMW"}};
    auto a = x.equal_range(2);
    for (auto b = a.first; b != a.second && b != x.cend(); ++b) {
        std::cout << b->first << ": " << b->second << std::endl;
    }
    return 0;
}

Output

If we run the above code it will generate the following output −

2: Cruze
2: Sail