allocator::difference_type
A signed integral type that can represent the difference between values of pointers to the type of object managed by the allocator.
typedef ptrdiff_t difference_type;
Remarks
The signed integer type describes an object that can represent the difference between the addresses of any two elements in a sequence that an object of template class allocator can allocate.
Example
// allocator_diff_type.cpp
// compile with: /EHsc
#include <memory>
#include <iostream>
#include <vector>
using namespace std;
int main( )
{
vector <int> v1;
vector <int>::iterator v1Iter;
vector <int>:: allocator_type v1Alloc;
int i;
for ( i = 0 ; i <= 7 ; i++ )
{
v1.push_back( i * 2 );
}
cout << "The original vector v1 is:\n ( " ;
for ( v1Iter = v1.begin( ) ; v1Iter != v1.end( ) ; v1Iter++ )
cout << *v1Iter << " ";
cout << ")." << endl;
allocator<int>::const_pointer v1PtrA, v1PtrB;
const int kA = 4, kB =12;
v1PtrA = v1Alloc.address( kA );
v1PtrB = v1Alloc.address( kB );
allocator<int>::difference_type v1diff = *v1PtrB - *v1PtrA;
cout << "Pointer v1PtrA addresses " << *v1PtrA << "." << endl;
cout << "Pointer v1PtrB addresses " << *v1PtrB << "." << endl;
cout << "The difference between the integer's addresses is: "
<< v1diff << "." << endl;
}
The original vector v1 is: ( 0 2 4 6 8 10 12 14 ). Pointer v1PtrA addresses 4. Pointer v1PtrB addresses 12. The difference between the integer's addresses is: 8.
Requirements
Header: <memory>
Namespace: std