vector::insert

下面是微软官方解释，很直观，很详细，顺手ctrl+c, ctrl+v

http://technet.microsoft.com/zh-cn/library/s5bta5ha(v=VS.80).aspx

vector::insert 

Inserts an element or a number of elements or a range of elements into the vector at a specified position.

iterator insert(
   iterator _Where,
   const Type& _Val
);
void insert(
   iterator _Where,
   size_type _Count,
   const Type& _Val
);
template<class InputIterator>
      void insert(
      iterator _Where,
      InputIterator _First,
      InputIterator _Last
   );

Parameters

_Where

The position in the vector where the first element is inserted.

_Val

The value of the element being inserted into the vector.

_Count

The number of elements being inserted into the vector.

_First

The position of the first element in the range of elements to be copied.

_Last

The position of the first element beyond the range of elements to be copied.

//============================================================================

// vector_insert.cpp
// compile with: /EHsc
#include <vector>
#include <iostream>

int main( )
{
   using namespace std;   
   vector <int> v1;
   vector <int>::iterator Iter;
   
   v1.push_back( 10 );
   v1.push_back( 20 );
   v1.push_back( 30 );

   cout << "v1 =" ;
   for ( Iter = v1.begin( ) ; Iter != v1.end( ) ; Iter++ )
      cout << " " << *Iter;
   cout << endl;

   v1.insert( v1.begin( ) + 1, 40 );
   cout << "v1 =";
   for ( Iter = v1.begin( ) ; Iter != v1.end( ) ; Iter++ )
      cout << " " << *Iter;
   cout << endl;
   v1.insert( v1.begin( ) + 2, 4, 50 );

   cout << "v1 =";
   for ( Iter = v1.begin( ) ; Iter != v1.end( ) ; Iter++ )
      cout << " " << *Iter;
   cout << endl;

   v1.insert( v1.begin( )+1, v1.begin( )+2, v1.begin( )+4 );
   cout << "v1 =";
   for (Iter = v1.begin( ); Iter != v1.end( ); Iter++ )
      cout << " " << *Iter;
   cout << endl;
}

Output

v1 = 10 20 30
v1 = 10 40 20 30
v1 = 10 40 50 50 50 50 20 30
v1 = 10 50 50 40 50 50 50 50 20 30