The first and last element in vector as pointed to by begin() and end() - 1 : vector elements « vector « C++ Tutorial

1. C++ Tutorial
2. vector
3. vector elements

#include <iostream>
#include <vector>

using namespace std;

void show(const char *msg, vector<int> vect);

int main() {

  // Declare a vector that has an initial capacity of 10.
  vector<int> v(10);

  for(unsigned i=0; i < v.size(); ++i) v[i] = i*i;

  show("Contents of v: ", v);

  // the use of the subscripting operator.
  int sum = 0;
  for(unsigned i=0; i < v.size(); ++i) sum += v[i];
  double avg = sum / v.size();
  cout << "The average of the elements is " << avg << "\n\n";

  // Add elements to the end of v.
  v.push_back(100);
  v.push_back(121);

  show("v after pushing elements onto the end: ", v);
  cout << endl;

  // Now use pop_back() to remove one element.
  v.pop_back();
  show("v after back-popping one element: ", v);
  cout << endl;

  cout << "The first and last element in v as"
       << " pointed to by begin() and end()-1:\n"
       << *v.begin() << ", " << *(v.end()-1) << "\n\n";

  return 0;
}

void show(const char *msg, vector<int> vect) {
  cout << msg << endl;
  for(unsigned i=0; i < vect.size(); ++i)
    cout << vect[i] << endl;
}