ERASE()

This function is used to remove elements from containers such as std::vector, std::list, std::deque, std::map, std::set, and others in the Standard Template Library (STL). Its behavior and parameters vary slightly depending on the container type. For sequence containers like vector and list, erase() can remove a single element using an iterator or a range of elements using two iterators. For associative containers like map and set, it can remove elements by key, by iterator, or by a range of iterators. When called, erase() adjusts the container to maintain valid structure, and in the case of vectors or deques, this might involve shifting elements. Importantly, for containers like vector, erasing elements invalidates iterators and references to the erased and subsequent elements.

vectorName.erase(positionIterator);              // Removes a single element
vectorName.erase(startIterator, endIterator);    // Removes a range of elements

 * positionIterator: Iterator to the element to be removed (e.g., vec.begin() + index)
 * startIterator, endIterator: The range of elements to remove (endIterator is exclusive)

REMOVING A SINGLE ITEM

#include <iostream>
#include <vector>
using namespace std;

int main() {
    // Step 1: Initialize a vector of numbers
    vector<int> numbers = {10, 20, 30, 40, 50};

    // Step 2: Remove the third element (index 2, value 30)
    numbers.erase(numbers.begin() + 2);

    // Step 3: Print updated vector using a normal for loop
    cout << "Updated numbers:" << endl;
    for (int i = 0; i < 4; i++) {  // After erasing, vector has 4 elements
        cout << numbers[i] << " ";
    }

    return 0;
}

OUTPUT:
 Updated numbers:
 10 20 40 50

REMOVING A RANGE OF ITEMS

#include <iostream>
#include <vector>
using namespace std;

int main() {
    // Step 1: Initialize a vector of months
    vector<string> months = {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul"};

    // Step 2: Remove elements from index 2 (Mar) to index 5 (excluding Jul)
    months.erase(months.begin() + 2, months.begin() + 6);

    // Step 3: Print updated vector using normal for loop
    cout << "Remaining months:" << endl;
    for (int i = 0; i < 3; i++) {  // Remaining: Jan, Feb, Jul
        cout << months[i] << " ";
    }

    return 0;
}

OUTPUT:
 Remaining months:
 Jan Feb Jul 

VIA LOOPS

#include <iostream>
#include <vector>
using namespace std;

int main() {
    vector<int> purchases;
    int numPurchases, itemToRemove;

    // Input number of purchases
    cin >> numPurchases;

    // Input purchases and store them in the vector
    for (int i = 0; i < numPurchases; ++i) {
        int purchase;
        cin >> purchase;
        purchases.push_back(purchase);  // Add each purchase to the vector
    }

    // Input the item to remove
    cin >> itemToRemove;

    // Search for the item and remove it if found
    bool found = false;
    for (int i = 0; i < purchases.size(); ++i) {
        if (purchases[i] == itemToRemove) {
            purchases.erase(purchases.begin() + i);  // Remove the item if found
            found = true;
            break;  // Exit after the first match
        }
    }

    // Check if the item was found
    if (!found) {
        cout << "Item not found." << endl;  // Item not found
    }

    // Output the updated list of purchases using a normal for loop
    cout << "Updated purchases: ";
    for (int i = 0; i < purchases.size(); ++i) {
        cout << purchases[i] << " ";
    }
    cout << endl;

    return 0;
}