class vector{
public:
    int size;double *vec;
    vector(){}
    vector(int size){
        this->size=size;
        this->vec=new double[size];
    }
    ~vector(){
        delete [] (this->vec);
    }
    void copyvec(vector a){
        for(int i=0;i<size;i++)
            this->vec[i]=a.vec[i];
    }
};
int main(){
    vector b(3); b.vec[0]=2;b.vec[1]=3;b.vec[2]=4;
    vector x(3);
    x.copyvec(b);
    return 0;
}