Insert an Element at the Given Index
Syntax of insert() in Vector
vector_name.insert (position, val);
Parameters
The function accepts two parameters specified below:
- position – It specifies the iterator which points to the position where the insertion is to be done.
- val – It specifies the value to be inserted.
Example of insert() in vector
C++
// C++ program to illustrate the function of // vector_name.insert(position,val) #include <bits/stdc++.h> using namespace std; int main() { // Initialising the vector vector<int> vector_name{ 1, 2, 3, 4, 5 }; // Printing out the original vector cout << "Original vector :\n"; for (auto x : vector_name) cout << x << " "; cout << "\n"; // Inserting the value 100 at position 3(0-based // indexing) in the vector vector_name.insert(vector_name.begin() + 3, 100); // Printing the modified vector cout << "Vector after inserting 100 at position 3 :\n"; for (auto x : vector_name) cout << x << " "; cout << "\n"; // Inserting the value 500 at position 1(0-based // indexing) in the vector vector_name.insert(vector_name.begin() + 1, 500); // Printing the modified vector cout << "Vector after inserting 500 at position 1 :\n"; for (auto x : vector_name) cout << x << " "; return 0; } // This code is contributed by Abhijeet Kumar(abhijeet19403) |
Output
Original vector : 1 2 3 4 5 Vector after inserting 100 at position 3 : 1 2 3 100 4 5 Vector after inserting 500 at position 1 : 1 500 2 3 100 4 5
vector insert() Function in C++ STL
std::vector::insert() is a built-in function in C++ STL that inserts new elements before the element at the specified position, effectively increasing the container size by the number of elements inserted.
Time Complexity – Linear, O(N)
The insert function is overloaded to work on multiple cases which are as follows:
- Insert an element at the given index.
- Insert an element multiple times.
- Insert a range of elements at the given index.