Description :The vector::front() is a built-in function in C++ STL which is used to return a reference to the first element in a vector container.
Example:
// Creating a vector
std::vector<int> example;
// Add elements to the List
example.push_back(10);
example.push_back(20);
example.push_back(30);
example.push_back(40);
// get the first element using front()
int & ele = example.front();
// Print the first element
std::cout << ele;