Convert 2D array of points into 1D array

Question

I am struggling to convert a 2D array of points in a 1D array of ints. I wrote a wrapper class to do that for me (Array3D), which does the mapping for me with filling the underlying buffer, but it looks like the indexing is totally wrong, since when I print my 2D array and in comparison the buffer, it gives me different outputs.

The 2D point array has dimensions steps × number_of_robots. Therefore, the 1D buffer has a length of steps × number_of_robots × 2.

Idea is that

buffer[index(x,y,0)] corresponds to points[index(x,y)].x
buffer[index(x,y,1)] corresponds to points[index(x,y)].y

The output is wrong, since it should be identical when I print out the 2D point array and the 1D buffer. I read the row of points from a file, and therefore, they totally should be identical.

The points are derived from the input read by a file. How that is done seems unimportant. Fact is, that the output of main.cpp is:

(0, 4)  (0, 5)  (1, 5)  (2, 5)  (2, 4)  (3, 4)  (2, 4)  (2, 3)  (2, 2)  
(4, 0)  (4, -1) (4, 0)  (4, 1)  (3, 1)  (4, 1)  (4, 2)  (3, 2)  (2, 2)  

(0, 2)  (0, 3)  (1, 2)  (2, 2)  (2, 2)  (3, 3)  (2, 2)  (2, 2)  (2, 2)  
(1, 2)  (2, 2)  (2, 2)  (3, 3)  (2, 2)  (2, 2)  (2, 2)  (3, 3)  (2, 2)  

point.cpp

Point::Point(int a, int b) {
    x = a;
    y = b;
}

Array3D.cpp

template<class T>
int Array3D<T>::index(int x,int y,  int z) {
    return (x * ydim + y) * zdim + z;
}

template<class T>
T Array3D<T>::get( int x,  int y, int z) {
    return buffer[index(x,y,z)];
}

template<class T>
void Array3D<T>::set( int x,  int y, int z ,T n) {
    buffer[index(x,y,z)] = n;
}

Harvester.cpp

int Harvester::index(int t, int n) {
    return t*number_of_robots + n;
}

void Harvester::extract(Array3D<int> *array) {
    Point p;
    for(int t = 0; t < steps; t++ ) {
        for(int n = 0; n < number_of_robots; n++) {
            p = data[index(t,n)];
            array->set(t,n,0,p.x);
            array->set(t,n,1,p.x);
        }
    }
}

void Harvester::read_points(string filename) {
    string line;
    ifstream input;

    input.open(filename.c_str());

    input >> number_of_robots;

    int x, y;
    for(int n = 0; n < number_of_robots; n++) {
        if(input >> x >> y) {
            data[index(0,n)].x = x;
            data[index(0,n)].y = y;
            //cout << x << " " << y << endl;
        } else {
            cout << "Your file is bad, and you should feel bad!";
            return;
        }
    }
}

void Harvester::print_harvest() {
    for (int n = 0; n < number_of_robots; n++) {
        for (int t = 0; t < steps; t++) {
            data[index(t,n)].dump();
        }
        cout << endl;
    }
    cout << endl;
}

robots_002.txt

2
0 4
4 0

main.cpp

int main() {
    int mission_time;
    int number_of_robots;
    Point goal;
    string path;
    bool print = true;

    int choice = 2;    

    mission_time = 8;
    number_of_robots = 2;
    goal.x = 2;
    goal.y = 2;
    path = "robots_002.txt"; 

    int steps = mission_time + 1;

    Harvester h(mission_time, number_of_robots, goal);
    h.read_points("fixtures/" + path);
    h.run();


    int *buffer = new int[steps * number_of_robots * 2];
    Array3D<int> arr(steps, number_of_robots, 2, buffer);

    h.extract(&arr);

    h.print_harvest();
    for (int n = 0; n < number_of_robots; n++) {
        for (int t = 0; t < steps; t++) {
                printf("(%d, %d)\t", arr.get(t, n, 0), arr.get(t, n, 1));
        }
        cout << endl;
    }


    return 0;
}

Answer 1

still looking through but quick observation. In Harverster::extract, you are setting both to p.x

void Harvester::extract(Array3D<int> *array) {
    Point p;
    for(int t = 0; t < steps; t++ ) {
        for(int n = 0; n < number_of_robots; n++) {
            p = data[index(t,n)];
            array->set(t,n,0,p.x);
            array->set(t,n,1,p.x);  //<-- im thinking you want this to be p.y
        }
    }
}