Issue
I'm using a vector
in a C++ program and I need to pass a part of that vector
to a function.
If it was C, I would need to do the following (with arrays):
int arr[5] = {1, 2, 3, 4, 5};
func(arr+2); // Pass the part of the array {3, 4, 5}
Is there any other way than creating a new vector
with the last part?
Solution
A common approach is to pass iterator ranges. This will work with all types of ranges, including those belonging to standard library containers and plain arrays:
template <typename Iterator>
void func(Iterator start, Iterator end)
{
for (Iterator it = start; it !=end; ++it)
{
// do something
}
}
then
std::vector<int> v = ...;
func(v.begin()+2, v.end());
int arr[5] = {1, 2, 3, 4, 5};
func(arr+2, arr+5);
Note: Although the function works for all kinds of ranges, not all iterator types support the increment via operator+
used in v.begin()+2
. For alternatives, have a look at std::advance
and std::next
.
Answered By - juanchopanza Answer Checked By - Cary Denson (PHPFixing Admin)
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