STL-----------------adjacent_difference
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template <class InputIterator, class OutputIterator>
OutputIterator adjacent_difference ( InputIterator first, InputIterator last,
OutputIterator result );
template <class InputIterator, class OutputIterator, class BinaryOperation>
OutputIterator adjacent_difference ( InputIterator first, InputIterator last,
OutputIterator result, BinaryOperation binary_op );
If x represents an element in [first,last) and y represents an element in result, the ys can be calculated as:
y 0 = x 0
y 1 = x 1 - x 0
y 2 = x 2 - x 1
y 3 = x 3 - x 2
y 4 = x 4 - x 3
... ... ...
The default operation is to calculate the difference, but some other operation can be specified as binary_op instead.
The behavior of this function template is equivalent to:
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Parameters
- first, last
- Input iterators to the initial and final positions in a sequence. The range used is [first,last), which contains all the elements between first and last, including the element pointed by first but not the element pointed by last.
- result
- Output iterator to the initial position in the destination sequence where the differences are stored. The range starts at result and shall have a size large enough to contain as many elements as the range above ( [first,last)).
- binary_op
- Binary operation taking as arguments two elements of the type pointed by the InputIterator, and returning the result of the replacement for the difference operation. This can either be a pointer to a function or an object whose class overloads operator().
Return value
An iterator pointing to past the last element of the destination sequence where resulting elements have been stored.Example
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#include <iostream>
#include <functional>
#include <numeric>
using namespace std;
int myop (int x, int y) {return x+y;}
int main () {
int val[] = {1,2,3,5,9,11,12};
int result[7];
adjacent_difference (val, val+7, result);
cout << "using default adjacent_difference: ";
for (int i=0; i<7; i++) cout << result[i] << ' ';
cout << endl;
adjacent_difference (val, val+7, result, multiplies<int>());
cout << "using functional operation multiplies: ";
for (int i=0; i<7; i++) cout << result[i] << ' ';
cout << endl;
adjacent_difference (val, val+7, result, myop);
cout << "using custom function: ";
for (int i=0; i<7; i++) cout << result[i] << ' ';
cout << endl;
return 0;
}
#include <iostream>
#include <functional>
#include <numeric>
using namespace std;
int myop (int x, int y) {return x+y;}
int main () {
int val[] = {1,2,3,5,9,11,12};
int result[7];
adjacent_difference (val, val+7, result);
cout << "using default adjacent_difference: ";
for (int i=0; i<7; i++) cout << result[i] << ' ';
cout << endl;
adjacent_difference (val, val+7, result, multiplies<int>());
cout << "using functional operation multiplies: ";
for (int i=0; i<7; i++) cout << result[i] << ' ';
cout << endl;
adjacent_difference (val, val+7, result, myop);
cout << "using custom function: ";
for (int i=0; i<7; i++) cout << result[i] << ' ';
cout << endl;
return 0;
}
Output:
using default adjacent_difference: 1 1 1 2 4 2 1 using functional operation multiplies: 1 2 6 15 45 99 132 using custom function: 1 3 5 8 14 20 23 |
#include <iostream>
#include <functional>
#include <numeric>
using namespace std;
int myop (int x, int y) {return x+y;}
int main () {
int val[] = {1,2,3,5,9,11,12};
int result[7];
adjacent_difference (val, val+7, result);
cout << "using default adjacent_difference: ";
for (int i=0; i<7; i++) cout << result[i] << ' ';
cout << endl;
adjacent_difference (val, val+7, result, multiplies<int>());
cout << "using functional operation multiplies: ";
for (int i=0; i<7; i++) cout << result[i] << ' ';
cout << endl;
adjacent_difference (val, val+7, result, myop);
cout << "using custom function: ";
for (int i=0; i<7; i++) cout << result[i] << ' ';
cout << endl;
return 0;
}