std::vector example

#include <iostream>
#include <vector> // we should include vector before using it.

using namespace std;

int main()
{
    // creates a new vector. "std::" is not required if we use "using namespace std;"
    // Note that we have to pass int within < > to denote the type of the data
    // it is going to hold
    // These type of classes are called "template classes"
    std::vector<int> myVector;

    myVector.push_back(10); // inserts an elemet
    myVector.push_back(9);

    for ( int i = 0 ; i < 10 ; i++ )
    {
        myVector.push_back( i * 5 );
    }

   cout << "Size : " << myVector.size() << endl;  // print the size of the vector

   /*
    To iterate through the elements of a vector (or other std containers),
    we use iterator defined inside that class itself.
    the begin() and end() returns the respective ends of the container.
   */

   // start the iteration from the begining
   std::vector<int>::iterator itr = myVector.begin();

   // iterate untin the iterator hits the end of the container
   for ( ; itr != myVector.end(); itr++ )
   {
       int val = *itr; // * dereferences the iterator and returns the actual value.
       cout << "Value : " << val << endl;
   }

   cout << endl;

   // we can access vector elements by index as well.
   for ( int i = 0; i < myVector.size(); i++ )
   {
       int val = myVector[i];
       cout << "Index : " << i << "  " << "Value : " << val << endl;
   }



   return 0;
}