unordered_set emplace() function in C++ STL
The unordered_set::emplace() function is a built-in function in C++ STL which is used to insert an element in an unordered_set container. The element is inserted only if it is not already present in the container. This insertion also effectively increases the container size 1.
Parameter: This function accepts a single parameter element which is to be inserted in the unordered_set container.
Return Value: This function returns a pair on successful insertion. The pair consists of an iterator pointing to the newly inserted element and a boolean value True. If the element to be inserted is already present in the container then it returns a pair with an iterator pointing to the already present element and a boolean value false.
Below programs illustrate the unordered_set::emplace() function:
sampleSet contains: 25 5 10 15 20
sampleSet contains: Welcome To GeeksforGeeks For Geeks Computer Science Portal
Time complexity: O(n)