checked_array_iterator Class
The checked_array_iterator class allows you to transform an array or pointer into a checked iterator.
For a list of all members of this type, see checked_array_iterator Members.
备注
This class is a Microsoft extension to the Standard C++ Library. Code implemented using this algorithm will not be portable. For an example demonstrating how to write code that does not require the use of this class, see the second example below.
template <class _Iterator>
class checked_array_iterator
: public iterator<
typename iterator_traits<_Iterator>::iterator_category,
typename iterator_traits<_Iterator>::value_type,
typename iterator_traits<_Iterator>::difference_type,
typename iterator_traits<_Iterator>::pointer,
typename iterator_traits<_Iterator>::reference>
Remarks
This class is defined in the stdext namespace.
For more information on the checked iterator feature, see Checked Iterators.
Example
The following sample shows how to define and use a checked array iterator.
If the destination is not large enough to hold all the elements being copied, such as would be the case if you changed the line:
copy(a, a + 5, checked_array_iterator<int*>(b, 5));
to
copy(a, a + 5, checked_array_iterator<int*>(b, 4));
A runtime error will occur.
// checked_array_iterator_overview.cpp
// compile with: /EHsc
#include <algorithm>
#include <iostream>
using namespace std;
using namespace stdext;
int main() {
int a[]={0, 1, 2, 3, 4};
int b[5];
copy(a, a + 5, checked_array_iterator<int*>(b, 5));
cout << "(";
for (int i = 0 ; i < 5 ; i++)
cout << " " << b[i];
cout << " )" << endl;
// constructor example
checked_array_iterator<int*> checked_out_iter(b, 5);
copy(a, a + 5, checked_out_iter);
cout << "(";
for (int i = 0 ; i < 5 ; i++)
cout << " " << b[i];
cout << " )" << endl;
}
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To avoid the need for the checked_array_iterator class when using Standard C++ Library algorithms, consider using a vector instead of a dynamically allocated array. The following example demonstrates how to do this.
// checked_array_iterator_2.cpp
// compile with: /EHsc
#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;
int main()
{
std::vector<int> v(10);
int *arr = new int[10];
for (int i = 0; i < 10; ++i)
{
v[i] = i;
arr[i] = i;
}
// std::copy(v.begin(), v.end(), arr); will result in
// warning C4996. To avoid this warning while using int *,
// use the Microsoft extension checked_array_iterator.
std::copy(v.begin(), v.end(),
stdext::checked_array_iterator<int *>(arr, 10));
// Instead of using stdext::checked_array_iterator and int *,
// consider using std::vector to encapsulate the array. This will
// result in no warnings, and the code will be portable.
std::vector<int> arr2(10); // Similar to int *arr = new int[10];
std::copy(v.begin(), v.end(), arr2.begin());
for (int j = 0; j < arr2.size(); ++j)
{
cout << " " << arr2[j];
}
cout << endl;
return 0;
}
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Requirements
Header: <iterator>
Namespace: stdext