C++primer习题3.18改变元素值

#include <iostream>
#include <vector>
using namespace std;

int main()
{
  vector<int> vec(10);
  for (size_t i = 0; i < 10; ++i)
  {
          cin >> vec[i];
  }
  vector<int>::iterator iter = vec.begin();
  cout << "The beginning number is:" <<endl;
  for (; iter != vec.end(); ++iter)
  {
          cout << *iter << " ";
  }
  cout << endl << "The end is:" << endl;
  for (iter = vec.begin();iter != vec.end(); ++iter)
  {
          *iter = *iter * 2;
       cout << *iter << " ";
  }
  cout << endl;
}