TODO:DESCRIPTION
emphasis.cpp
:
#include <iostream>
#include <vector>
#include <algorithm>
typedef std::pair<double, double> Point;
typedef std::vector<Point> Polygon;
Point emphasis(const Polygon & polygon)
{
if (polygon.size() < 3) return Point(0.0, 0.0);
Point a(0.0, 0.0);
std::for_each (polygon.begin(), polygon.end(), [&a](const Point & p)
{
a.first += p.first;
a.second += p.second;
});
return Point(a.first / polygon.size(), a.second / polygon.size());
}
int main(int, char **)
{
Polygon polygon =
{
Point(5, 5),
Point(7, 5),
Point(8, 10),
Point(5, 12),
Point(3, 7),
};
Point e = emphasis(polygon);
std::cout << "emphasis of non-selfintersection polygon: ("
<< e.first << ","
<< e.second << ")"
<< std::endl;
return 0;
}
emphasis.scm
:
(define (vec-add v)
(cond
((null? v) '(0 0))
((not (list? v)) #f)
(else
(let ((x (car v)) (y (vec-add (cdr v))))
(list
(+ (car x) (car y))
(+ (cadr x) (cadr y)))))))
(define (calc-emphasis v)
(cond
((null? v) 0)
((= (length v) 0) 0)
(else
(let ((x (vec-add v)) (l (length v)))
(map (lambda (s) (/ s l)) x)))))
(define polygon '((5 5) (7 5) (8 10) (5 12) (3 7)))
(display "emphasis of ")
(display polygon)
(display " = ")
(display (calc-emphasis polygon))
(newline)
(exit)