векторы

#include <iostream>
#include <vector>

using namespace std;

int avg(vector<float> a){
    float res = 0;
    for (int i = 0; i < a.size(); i++)
        res += a[i];
    return (res / a.size());
}
class vec2d {
public:
    float x;
    float y;
    vec2d() : x(0), y(0) {}
    vec2d(float a,float b) : x(a), y(b){}
    void print(){
        cout << x << "\t" << y << endl;
    }
    float dot(vec2d other){
        return (x * other.x + y * other.y);
    }
    vec2d operator + (vec2d other){
        return vec2d(x + other.x, y + other.y);
    }
    vec2d operator - (vec2d other){
        return vec2d(x - other.x, y - other.y);
    }
    vec2d operator * (float a){
        return vec2d(x * a, y * a);
    }
    vec2d operator / (float a){
        return vec2d(x / a, y / a);
    }
};

int main()
{
    /*vector<float> arr;
    for (float i = 0; i < 9; i+= 1.1)
        arr.push_back(i*i);
    for (float i = 0; i < 9; i++)
        cout << arr[i] << "\n";
    cout << "--------------------------------------" << endl;
    cout << avg(arr) << endl;*/
    vec2d a(4,2);
    a.print();
    vec2d b(-1,-2);
    vec2d c = a - b;
    c.print();

    //cout << a.dot(b) << endl;
    return 0;
}