STL Containers Overviews

There are serveral container classes in STL. All of them are genetic template class and can work for any type of data:

• std::vector: Vectors are sequence containers representing arrays that can change in size. Support the method push_back(), pop_back(), insert(), remove(), size() and empty().
• std::list: Lists are sequence containers that allow constant time insert and erase operations anywhere within the sequence, and iteration in both directions. Support the method push_front, pop_front(), push_back(), pop_back(), insert(), remove(), size(), empty(), front() and back().
• std::forward_list: Forward lists are sequence containers that allow constant time insert and erase operations anywhere within the sequence.
• std::deque: deque is an irregular acronym of double-ended queue. Double-ended queues are sequence containers with dynamic sizes that can be expanded or contracted on both ends (either its front or its back).
• std::priority_queue: Priority queues are a type of container adaptors, specifically designed such that its first element is always the greatest of the elements it contains, according to some strict weak ordering criterion. Support the method push(), pop(), empty() and size()
• std::stack: Stacks are a type of container adaptor, specifically designed to operate in a LIFO context, where elements are inserted and extracted only from one end of the container. Support the method push_back(), pop_back(), empty() and size()
• std::set: Sets are containers that store unique elements following a specific order.
• std::multiset: Multisets are containers that store elements following a specific order, and where multiple elements can have equivalent values.

STL Classes

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

int main() {
  vector<int> v = { 2, 4, 6, 8, 10 };
  v.push_back(20);
  v.push_back(30);
  v.pop_back();

  // iterating vector use for-each loop
  for (int x:v) { cout << x << endl; }

  // iterating vector use iterator
  vector<int>::iterator itr;
  for (itr = v.begin(); itr != v.end(); itr++) { cout << *itr << endl; }
}

Map Classes

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

int main() {
  map<int, string> m;
  m.insert(pair<int, string>(1, "John"));
  m.insert(pair<int, string>(2, "Mark"));
  m.insert(pair<int, string>(3, "Khan"));

  // iterating with iterator
  map<int, string>::iterator itr1;
  for (itr1 = m.begin(); itr1 != m.end(); itr1++) {
    cout << itr1->first << " " << itr1->second << endl;
  }

  // searching pair with key
  map<int, string>::iterator itr2;
  itr2 = m.find(2);
  cout << itr2->first << " " << itr2->second << endl;
}