std::next returns an iterator pointing to the element after being advanced by certain no. of positions. It is defined inside the header file
.
It
does not modify its arguments and returns a copy of the argument advanced by the specified amount. If it is a
random-access iterator, the function uses just once operator + or operator - for advancing. Otherwise, the function uses repeatedly the increase or decrease operator (operator ++ or operator --) on the copied iterator until n elements have been advanced.
Syntax:
ForwardIterator next (ForwardIterator it,
typename iterator_traits::difference_type n = 1);
it: Iterator to the base position.
difference_type: It is the numerical type that represents
distances between iterators of the ForwardIterator type.
n: Total no. of positions by which the
iterator has to be advanced. In the syntax, n is assigned
a default value 1 so it will atleast advance by 1 position.
Returns: It returns an iterator to the element
n positions away from it.
CPP
// C++ program to demonstrate std::next
#include <iostream>
#include <iterator>
#include <deque>
#include <algorithm>
using namespace std;
int main()
{
// Declaring first container
deque<int> v1 = { 1, 2, 3, 4, 5, 6, 7 };
// Declaring another container
deque<int> v2 = { 8, 9, 10 };
// Declaring an iterator
deque<int>::iterator i1;
// i1 points to 1
i1 = v1.begin();
// Declaring another iterator to store return
// value and using std::next
deque<int>::iterator i2;
i2 = std::next(i1, 4);
// Using std::copy
std::copy(i1, i2, std::back_inserter(v2));
// Remember, i1 stills points to 1
// and i2 points to 5
// v2 now contains 8 9 10 1 2 3 4
// Displaying v1 and v2
cout << "v1 = ";
int i;
for (i = 0; i < 7; ++i) {
cout << v1[i] << " ";
}
cout << "\nv2 = ";
for (i = 0; i < 7; ++i) {
cout << v2[i] << " ";
}
return 0;
}
Output:
v1 = 1 2 3 4 5 6 7
v2 = 8 9 10 1 2 3 4
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