I have a little problem in C++ and i hope you are able to help me out.
I want to define a struct myPoint. This struct should be able to compare two objects from type point (defined as pair). I want every "Instance" of myPoint to be able to compare two points on its own. This is what i tried to code:
typedef pair<int,int> point;
struct myPoint{
point p;
inline bool operator<( point x, point y ){
return !ccw(p,x,y);
}
So every myPoint should consider his own point p while comparing two points x,y. The (translated) Error I get is
"error C2804: Binary Operator '<' has too much Arguments/Parameters"
It seems like it's syntacticly possible to make this operator with only one point, I guess the it would compare a point to a myPoint, but that's not what it should be. Background of the problem is that i want to use a predefined sort function to sort a vector of points and as sorting "function" I want to deliver a myPoint object.
I think (maybe) that what you are trying to do is write a functor
struct myPoint
{
myPoint(point p) { this->p = p; }
bool operator()(point x, point y) const
{
return !ccw(p,x,y);
}
point p;
};
A functor can be passed as the third argument to std::sort.
std::sort(vec.begin(), vec.end(), myPoint(p));
I have my doubts though, assuming ccw means counterclockwise I don't think this is a valid sort condition.
The <
defines overload with only one parameter. As noted by @KonradRudolph, it makes no sense to overload <
in this case 'cause you couldn't use it in sorting or anything
typedef pair<int,int> point;
struct myPoint{
point p;
bool smaller(const point &a, const point &b)
{
return !ccw(p,a,a)
}
};
This fragment should illustrate basic things for you:
#include <utility>
typedef std::pair<int,int> point;
bool less(const point& p1, const point& p2)
{
return (p1.first < p2.first) ||
((p1.first == p2.first) && (p1.second == p2.second));
}
struct myPoint {
point p;
inline bool operator < (const point& p2) {
return less(p, p2);
}
};
int main()
{
return 0;
}
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