C++ Working of STL Set find() Method Program

Hello Everyone!

In this tutorial, we will learn about the working of the find() method in STL and its implementation using Set in the C++ programming language.

What is a Set?

In programming, a Set is used to store unique values of a list and also automatically providing an ordering to its elements. By default, the ordering is in ascending order.

The elements are inserted using the insert() method. If the same value is inserted multiple times, the set automatically deletes the duplicates and only store the single copy of that element.

The elements of the Set are deleted using the erase() method.

The find(x) method returns an iterator to the element which is searched in the set container (x in this case). If the element is not found, then the iterator points to the position just after the last element in the set.

For a better understanding of its implementation, refer to the well-commented C++ code given below.

Code:

#include <iostream>
#include <bits/stdc++.h>

using namespace std;

//Function to print the elements of the set using an iterator
void show(set<int> s)
{
    //declaring an iterator to iterate through the set
    set<int>::iterator i;

    for (i = s.begin(); i != s.end(); i++)
    {
        cout << *i << "  "; //accessing the elements of the set using * as i stores the address to each element
    }

    cout << endl;
}

int main()
{
    cout << "\n\nWelcome to Studytonight :-)\n\n\n";
    cout << " =====  Program to demonstrate the working of find() method of STL, in CPP  ===== \n\n\n\n";

    cout << " ***  find(x) methods returns a pointer to the element x if present, and pointer to end element if not present.  *** \n\n";

    //Set declaration (Set of integers)
    set<int> s;

    //Filling the elements by using the insert() method.
    cout << "\n\nFilling the Set with integers in random order."; //Set automatically stores them in order

    s.insert(5);
    s.insert(39);
    s.insert(64);
    s.insert(82);
    s.insert(35);
    s.insert(54);

    cout << "\n\nThe elements of the Set are: ";
    show(s);

    set<int>::iterator it;

    //An iterator pointing to the element 39
    it = s.find(39);

    cout << "\n\nPrinting the elements of the Set that are greater than or equal to 39 : ";

    for (; it != s.end(); it++)
    {
        cout << " " << *it;
    }

    cout << "\n\nAfter deleting the element 39 from the set using the erase() method, it becomes: ";
    s.erase(39);
    show(s);

    //An iterator pointing to the element 39
    it = s.find(39);

    if (it == s.end())
        cout << "\n\nElement 39 is not present in the Set.";

    cout << "\n\n\n";

    return 0;
}

Output:

We hope that this post helped you develop a better understanding of the concept of find() method in Set and its implementation in C++. For any query, feel free to reach out to us via the comments section down below.

Keep Learning : )