hashset in cpp

A hashset in C++ is a container that stores unique elements in no particular order. It uses a hash function to map the elements to their corresponding positions in the container. Here's an explanation of the steps involved in using a hashset in C++:

  1. Include the necessary header file: To use the hashset in C++, you need to include the <unordered_set> header file.

  2. Declare a hashset: Declare a hashset variable using the unordered_set template. You can specify the data type of the elements you want to store in the hashset as a template argument. For example, to declare a hashset of integers, you can write:

std::unordered_set<int> myHashSet;
  1. Insert elements: Use the insert() function to insert elements into the hashset. The insert() function takes the element as an argument and adds it to the hashset if it doesn't already exist. For example:
  1. Check if an element exists: You can use the count() function to check if a specific element exists in the hashset. The count() function returns 1 if the element is present and 0 otherwise. For example:
if (myHashSet.count(20) == 1) {
    // Element 20 exists in the hashset
} else {
    // Element 20 doesn't exist in the hashset
  1. Remove elements: To remove an element from the hashset, you can use the erase() function. The erase() function takes the element as an argument and removes it from the hashset if it exists. For example:
  1. Iterate over elements: You can use a range-based for loop to iterate over all the elements in the hashset. For example:
for (const auto& element : myHashSet) {
    // Process each element

These are the basic steps involved in using a hashset in C++. Keep in mind that the order of elements in a hashset is not guaranteed, as they are stored based on their hash values.