C++ unordered set Methods
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In C++, the std::unordered_set
container provides a number of methods that allow you to manipulate the contents of the set. Here are some of the most commonly used methods:
Inserting Elements
- `insert()`: Inserts a new element into the set.std::unordered_set<int> mySet; mySet.insert(1); // Inserts the value 1 into the set
Removing Elements
- `erase()`: Removes an element from the set.std::unordered_set<int> mySet = {1, 2, 3}; mySet.erase(2); // Removes the value 2 from the set
clear()
: Removes all elements from the set.
std::unordered_set<int> mySet = {1, 2, 3}; mySet.clear(); // Removes all elements from the set
Finding Elements
- `find()`: Searches the set for an element with a given value, and returns an iterator to the element if found.std::unordered_set<int> mySet = {1, 2, 3}; auto it = mySet.find(2); // Searches for the value 2 in the set if (it != mySet.end()) { std::cout << "Found: " << *it << std::endl; } else { std::cout << "Not found" << std::endl; }
Checking the Size of the Set
- `size()`: Returns the number of elements in the set.std::unordered_set<int> mySet = {1, 2, 3}; std::cout << "Size: " << mySet.size() << std::endl; // Prints "Size: 3"
Iterating over the Elements of the Set
You can use a ranged for loop to iterate over the elements of an unordered set:std::unordered_set<int> mySet = {1, 2, 3}; for (const auto& elem : mySet) { std::cout << elem << " "; } std::cout << std::endl;
This will print the elements of the set in no particular order.