C++ map - end() Function

The C++ map::end function returns the iterator pointing to the past-the-last element of the map container. The past-the-last element of the map is the theoretical element that follows the last element. It does not point to any element, and hence could not be dereferenced.

Note: Map is an ordered data container which implies all its elements are ordered all the time.

Syntax

• C++98
• C++11

iterator end();
const_iterator end() const;

iterator end() noexcept;
const_iterator end() const noexcept;

Parameters

No parameter is required.

Return Value

An iterator to the past-the-last element of the sequence container. If the sequence object is constant qualified, the function returns a const_iterator, else returns an iterator.

Time Complexity

Constant i.e, Θ(1).

Example:

In the example below, the map::end function returns the iterator pointing to the past-the-last element of the map MyMap.

#include <iostream>
#include <map>
using namespace std;
 
int main (){
  map<int, string> MyMap;
  map<int, string>::iterator it;

  MyMap[101] = "John";
  MyMap[102] = "Marry";
  MyMap[103] = "Kim";
  MyMap[104] = "Jo";
  MyMap[105] = "Ramesh";

  it = MyMap.end();
  it--;
  cout<<it->first<<" "<<it->second<<"\n";
  it--;
  cout<<it->first<<" "<<it->second<<"\n";
  it--;
  cout<<it->first<<" "<<it->second<<"\n";
  return 0;
}

The output of the above code will be:

105 Ramesh
104 Jo
103 Kim

Example:

Lets see another example of map where map::end function is used with map::begin function to specify a range including all elements of the map container.

#include <iostream>
#include <map>
using namespace std;
 
int main (){
  map<string, int> MyMap;
  map<string, int>::iterator it;

  MyMap["John"] = 2500;
  MyMap["Jack"] = 2600;
  MyMap["Ella"] = 2000;
  MyMap["Nora"] = 3000;
  MyMap["Adam"] = 3100;

  cout<<"MyMap contains: \n ";
  for(it = MyMap.begin(); it != MyMap.end(); ++it)
    cout<<it->first<<"  "<<it->second<<"\n ";

  return 0;
}

The output of the above code will be:

MyMap contains: 
 Adam  3100
 Ella  2000
 Jack  2600
 John  2500
 Nora  3000