How to Remove Last Element from Vector in C++?

Given a vector of n elements, the task is to remove the last element from the vector in C++.

The most efficient method to remove the last element from vector is by using vector pop_back() method. Let’s take a look at a simple example:

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

int main() {
    vector<int> v = {1, 5, 7, 9};

    // Remove the last element 9
    v.pop_back();

    for (auto i : v)
        cout << i << " ";
    return 0;
}

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Explanation: The vector pop_back() function remove the last element from vector directly and does not return any value.

There are also some other methods in C++ by which we can remove the last element from vector. Some of them are as follows:

Using vector erase()

The vector erase() function can also be used to remove the last element from vector by specifying the position.

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

int main() {
    vector<int> v = {1, 5, 7, 9};

    // Remove the last element 9
    v.erase(--v.end());

    for (auto i : v)
        cout << i << " ";
    return 0;
}

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Explanation: In this method, we provide an iterator to the last element of vector and it will remove an element of given position.

Using vector resize()

The vector resize() method is used to resize the size of vector. If we resize the vector to the size less that the current size, the extra elements are deleted from the end. So, by reducing the size by 1, we can delete the last element from the vector.

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

int main() {
    vector<int> v = {1, 5, 7, 9};

    // Remove the last element 9
    v.resize(v.size() - 1);

    for (auto i : v)
        cout << i << " ";
    return 0;
}

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Article Tags :

• C++ Programs
• C++
• STL
• cpp-vector
• CPP Examples

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