Check out example codes for "vector last c++". It will help you in understanding the concepts better.

Code Example 1

vector<int> v;
cout << v[v.size() - 1];
cout << *(v.end() - 1);
cout << *v.rbegin();
// all three of them work

Code Example 2

// vector::back
#include <iostream>
#include <vector>

int main ()
{
  std::vector<int> myvector;

  myvector.push_back(10);

  while (myvector.back() != 0)
  {
    myvector.push_back ( myvector.back() -1 );
  }

  std::cout << "myvector contains:";
  for (unsigned i=0; i<myvector.size() ; i++)
    std::cout << ' ' << myvector[i];
  std::cout << '\n';

  return 0;
}

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