How to Traverse a Map Using Iterator in C++?
Last Updated :
04 Mar, 2024
In C++, maps are associative containers that store elements where each element has a key value and a mapped value. An iterator is a pointer-like object that allows traversing through the elements of a container like a map. In this article, we will learn how to traverse a map using an iterator in C++.
Example :
Input:
myMap[1] = "One";
myMap[2] = "Two";
myMap[3] = "Three";
myMap[4] = "Four";
Output:
Here is the map : {
{1, One},
{2, Two},
{3, Three},
{4, Four} }
Traverse a Map Using Iterator in C++
To traverse a std::map using an iterator, we can use the std::map::begin() function to get an iterator pointing to the first element of the map and the std::map::end() function to get an iterator pointing one past the last element of the map. Then we can increment the iterator in a loop to traverse through the elements.
C++ Program to Traverse a Map Using an Iterator
C++
#include <iostream>
#include <map>
using namespace std;
int main()
{
map< int , string> myMap;
myMap[1] = "One" ;
myMap[2] = "Two" ;
myMap[3] = "Three" ;
myMap[4] = "Four" ;
myMap[5] = "Five" ;
map< int , string>::iterator it;
cout << "Here is the map : {" << endl;
for (it = myMap.begin(); it != myMap.end(); ++it) {
cout << " {" << it->first << ", " << it->second
<< "} " << endl;
}
cout << '}' << endl;
cout << "One full iteration complete." ;
return 0;
}
|
Output
Here is the map : {
{1, One}
{2, Two}
{3, Three}
{4, Four}
{5, Five}
}
One full iteration complete.
Time Complexity: O(n), where n is the number of elements in the map.
Auxiliary Space: O(1)
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