Return iterator to beginning


Returns an iterator pointing to the first element in the ​​vector​​.


Notice that, unlike member ​​vector::front​​​, which returns a reference to the first element, this function returns a​​random access iterator​​ pointing to it.


If the container is ​​empty​​, the returned iterator value shall not be dereferenced.



Parameters(参数)


none



Return Value


An iterator to the beginning of the sequence container.


If the ​​vector​​ object is const-qualified, the function returns a const_iterator. Otherwise, it returns an iterator.



Member types iterator and const_iterator are ​​random access iterator​​ types (pointing to an element and to a const element, respectively).


// vector::begin/end
#include <iostream>
#include <vector>
using namespace std;
int main ()
{
  vector<int> myvector;
  for (int i=1; i<=5; i++) myvector.push_back(i);

  cout << "myvector contains:";
  for (vector<int>::iterator it = myvector.begin() ; it != myvector.end(); ++it)
   cout << ' ' << *it;
    cout << endl;
  return 0;
}


---------------------------------------------------

// vector::begin/end
#include <iostream>
#include <vector>
using namespace std;
int main ()
{
  vector<int> myvector;
  for (int i=1; i<=5; i++) myvector.push_back(i);

  cout << "myvector contains:";
  vector<int>::iterator it;
  
  for (it = myvector.begin() ; it != myvector.end(); ++it)
   cout << ' ' << *it;
    cout << endl;
  return 0;
}




Output:



myvector contains: 1 2 3 4 5




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