Question

I am trying sort std::vector using algorithm::sort , But I am getting runtime error
Invalid operator <.

Following is my code.

struct Point {
    double x_cord;
    double y_cord;
    int id;
    Point(int d, double x, double y) {
        x_cord = x;
        y_cord = y;
        id = d;
    }
};

struct compareX {
    bool operator ()(Point * left, Point* right) const {
        if (left->x_cord < right->x_cord) 
            return true;
        return true;
    }
};
struct compareY {
    bool operator ()(Point * left, Point* right) const {
        if (left->y_cord <= right->y_cord) return true;
        return true;
    }
};

Here is now I am calling it after populating the values.

std::sort( posVector.begin(), posVector.end(), compareX());

Answer 1

Your comparison function always returns true!