How to Create Stack of Unordered Set in C++? Last Updated : 04 Mar, 2024 Summarize Comments Improve Suggest changes Share Like Article Like Report In C++, a stack is a container adapter that provides a Last-In-First-Out (LIFO) type of data structure, and an unordered set is a container that stores unique elements in no particular order. In this article, we will learn how to create a stack of unordered sets in C++. Creating a Stack of Unordered Sets in C++To create a std::stack of std::unordered_set, we can use the std::stack template class that takes the type of the elements as a template parameter. We can define this type as of unordered_set of a given type. Syntax to Declare Stack of Unordered Setstack<unordered_set<Type>> myStackC++ Program to Create Stack of Unordered Set C++ // C++ program to illustrate how to create a stack of // unordered sets in C++ #include <iostream> #include <stack> #include <unordered_set> using namespace std; int main() { // Declaring a stack of unordered sets stack<unordered_set<int> > myStack; // Creating some unordered sets unordered_set<int> set1 = { 1, 2, 3 }; unordered_set<int> set2 = { 4, 5, 6 }; unordered_set<int> set3 = { 7, 8, 9 }; // Pushing unordered sets into the stack myStack.push(set1); myStack.push(set2); myStack.push(set3); // Checking if the stack is empty cout << "Stack Elements: " << endl; while (!myStack.empty()) { auto ele = myStack.top(); int count = 1; cout << "uSet" << count << ": "; for (auto i : ele) { cout << i << " "; } count++; cout << endl; myStack.pop(); } return 0; } OutputStack Elements: uSet1: 9 7 8 uSet1: 6 4 5 uSet1: 3 1 2 Time Complexity: O(N) where, N is the number of unordered sets.Auxiliary Space: O(N) Comment More infoAdvertise with us Next Article How to Create a Stack of Unordered_Multimap in C++? R rohitpant4532 Follow Improve Article Tags : C++ Programs C++ STL cpp-unordered_map cpp-stack CPP Examples +2 More Practice Tags : CPPSTL Similar Reads How to Create a Stack of Unordered_Map in C++? In C++, the stack is a container that follows the LIFO(Last In First Out) rule where new elements are added from one end (top) and removed from that end only. An unordered_map is an associative container that stores elements formed by a combination of key-value pairs, where the key should be unique. 2 min read How to Create a Stack of Unordered_Multiset in C++? In C++, the stack is a container in which new elements are added from one end (top) and removed from that end only. In this article, we will learn how to create a stack of unordered_multiset in C++. Example: Input: mySet1 = { âappleâ, âbananaâ, âappleâ } mySet2 = { âorangeâ, âmangoâ, âorangeâ } Outp 2 min read How to Create Deque of Unordered_Set in C++? In C++, a deque (double-ended queue) is a container that allows insertion and removal of elements from both ends whereas an unordered set is a container that stores unique elements in no particular order. In this article, we will learn how to create a deque of unordered sets in C++ STL. Example:Inpu 2 min read How to Create a Stack of Set in C++? In C++ STL, Stacks are a type of container adaptor with LIFO(Last In First Out) type of working, where a new element is added at one end (top) and an element is removed from that end only. Sets are a type of associative container in which each element is unique and in some sorted order. In this arti 2 min read How to Create a Stack of Unordered_Multimap in C++? In C++, an unordered_multimap is an associative container that contains key-value pairs allowing multiple elements with the same key. In this article, we will learn how to create a stack of unordered_multimaps in C++. Example: Input: myMultimap1 = { {1, âC++â}, {2, âJavaâ}, {1, âPythonâ} }; myMultim 2 min read How to Create Stack of Tuples in C++? In C++, a stack is a container adapter that provides a LIFO (Last In First Out) order of element insertion and deletion which is only possible at the end. A tuple is a container that can store elements of different types. In this article, we will learn how to create a stack of tuples in C++. Example 2 min read Like