Home » C++ STL

set::insert() function in C++ STL

C++ STL set::insert() function: Here, we are going to learn about the insert() function of set in C++ STL (Standard Template Library).
Submitted by Radib Kar, on February 16, 2019

C++ STL set::insert() function

set::insert() function is a predefined function, it is used to insert an element to the set container.

Prototype:

    set<T> st; //declaration
    st.insert(T item);

Parameter:

    T item; //T is the data type

Return type: Iterator pointer to the inserted value

Usage: The function inserts elements to the set.

Time complexity: O(1)

Example:

    For a set of integer,
    set<int> st;
    st.insert(5);
    st.insert(4);

    set content: //sorted always(ordered)
        4
        5

Header file to be included:

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

C++ implementation:

#include <bits/stdc++.h>
using namespace std;

void printSet(set<int> st){
	set<int>:: iterator it;
	cout<<"Set contents are:\n";
	for(it=st.begin();it!=st.end();it++)
		cout<<*it<<" ";
	cout<<endl;
}

int main(){
	cout<<"Example of insert function\n";
	set<int> st;
	set<int>:: iterator it;
	cout<<"inserting 4\n";
	st.insert(4);
	cout<<"inserting 6\n";
	st.insert(6);
	cout<<"inserting 10\n";
	st.insert(10);

	printSet(st); //printing current set

	return 0;
}

Output

Example of insert function
inserting 4
inserting 6
inserting 10
Set contents are:
4 6 10