You can store pairs in vectors to create collections of related value pairs. This is common for representing edges in graphs, coordinates, or any paired data. Declaration: vector<pair<int, int>> edges; To add elements: edges.push_back(make_pair(1, 2)); or edges.push_back({1, 2}); The brace syntax works in C++11 and later.
Access elements with indices: edges[0].first and edges[0].second. Iterate with range-based for: for (auto& e : edges) { cout << e.first << " " << e.second; } Vectors of pairs are common in competitive programming for storing graph edges, sorting by custom criteria, and grouping related values together.