How to Access Element by Index in a Set

C++ set find – How to Access Element by Index in a Set | C++

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Set: How to access set elements in c++ or access set elements c++.

C++ set find: A Set is used in programming to store unique values of a list while also automatically providing an ordering to its elements. The ordering is set to ascending by default.

The insert() method is used to insert the elements. If the same value is inserted more than once, the set automatically deletes the duplicates and stores only one copy of that variable.

The erase() method is used to remove the Set’s components.

Examples:

Input:

set ={ "hello", "this", "is" , "BTechGeeks" , "platform"} index =2

Output:

2rd Element in set = this

Accessing elements by index in a Set

C++ set find: std::set is an associative container that stores elements in a balanced binary search tree internally and does not support the random access operator [].

As a result, getting a random element from a set by index (C++ Set Get Element By Index) is a little tricky.

The elements of the set will be stored in sorted order.

There are several ways to access elements by index in a set some of them are:

Method #1:Using iterator and generic approach

Set find c++: To access an element at the nth index, we must first construct an iterator pointing to the starting position and continue to increment the iterator until the nth element is reached.

Below is the implementation:

#include <bits/stdc++.h>
using namespace std;
int main()
{
    // creating a string set and initializing with some
    // strings
    set<string> stringset = { "Hello", "this", "Hello",
                              "this", "BTechGeeks" };
    // given index
    int index = 2;
    set<string>::iterator setItr = stringset.begin();
    for (int i = 0; i < index; i++)
        setItr++;
    cout << index << "rd Element in set = " << *setItr
         << endl;
}

Output:

2rd Element in set = this

Method #2:Using std::advance

Find in set c++: std::advance takes an iterator and a value to advance the specified iterator. Let’s look at how to use std::advance to access an index feature.

Below is the implementation:

#include <bits/stdc++.h>
using namespace std;
int main()
{
    // creating a string set and initializing with some
    // strings
    set<string> stringset = { "Hello", "this", "Hello",
                       h3       "this", "BTechGeeks" };
    // given index
    int index = 2;
    set<string>::iterator setItr = stringset.begin();
    // It will advance the passed iterator by the index
    // value.
    advance(setItr, index);
    cout << index << "rd Element in set = " << *setItr
         << endl;
}

Output:

2rd Element in set = this

Method #3:Using std::next

Set string c++: It was implemented in C++11, and unlike std::advance, it does not increment the given iterator, but rather returns a new iterator that is n positions advanced to the given iterator.
Let’s look at how to use std::next to get to the index element.
Below is the implementation:

#include <bits/stdc++.h>
using namespace std;
int main()
{
    // creating a string set and initializing with some
    // strings
    set<string> stringset = { "Hello", "this", "Hello",
                              "this", "BTechGeeks" };
    // given index
    int index = 2;

    // Internally, std::next iterates over n elements to
    // reach the nth element and
    // returns the iterator of the set's index element.
    set<string>::iterator setItr
        = next(stringset.begin(), index);
    cout << index << "rd Element in set = " << *setItr
         << endl;
}

Output:

2rd Element in set = this

Recommended Reading On: Different ways to Erase / Delete an element from a Set in C++

Try these: 

  1. How To Access Elements In Set C++
  2. How To Access Elements Of Set
  3. How To Access An Element In A Set C++
  4. How To Access The Elements Of A Set In C++
  5. How To Access A Element In Set.
  6. Accessing Set Elements In C++
  7. Get Nth Element Of Set C++
  8. Access Nth Element In Set C++

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