Weird Behaviour in C++ Snake School Assignment - c++

Question

So over the last few weeks we've been coding snake in c++ step by step. Right now we have to implement the snake actually growing. (All of this happens in the console)
We realize the growth by saving the head and the tail of the snake, as well as the Direction the Head went on a given field and then moving the tail into that saved direction from the field the tail is on.
Theoretically skipping this tail movement once when we eat a fruit should let our snake grow.
However, my Snake either doesnt grow at all, or grows infinitely until I pass the Field on which the fruit was again, or ,in this current iteration, grows mostly correct but only in the direction which I was facing when eating the fruit. Also in this Iteration the size of the snake changes, if I comment out the GenerateFruit() Command (Even when that command is completely empty).
I'm clueless as to what im doing wrong. I've had different behaviour just by having a literally empty if statement.
Heres the main part of the code:
bool MoveSnake(SnakeDataT snakeData){
//Collision detection: If the new x/y Coordinate hits the walls we have a collision.
if (snakeData.Head.x + snakeData.dx == WIDTH - 1 || snakeData.Head.x + snakeData.dx == 0 || snakeData.Head.y + snakeData.dy == HEIGHT + 1 || snakeData.Head.y + snakeData.dy == 0)
{
SetCursor(WIDTH, HEIGHT);
cout << "\n";
cout << "\n";
cout << "\n";
cout << "Game Over" << endl;
return false;
}
//Save current Movement Direction in current coordinate
snakeData.Field[snakeData.Head.x][snakeData.Head.y].dx = snakeData.dx;
snakeData.Field[snakeData.Head.x][snakeData.Head.y].dy = snakeData.dy;
//Fruit Collision:
if (snakeData.Head.x == snakeData.Fruit.x && snakeData.Head.y == snakeData.Fruit.y)
{
//GenerateFruit(snakeData); <- If I leave this out it literally changes behaviour?!
}
else if (!(snakeData.Head.x == snakeData.Fruit.x && snakeData.Head.y == snakeData.Fruit.y))
{
//Delete at Tail Position
SetCursor(snakeData.Tail.x, snakeData.Tail.y);
cout << ' ';
//Move Tail by saved Direction. I did try this with the Tail coordinates first, but after many different iterations this showed the weirdest results.
snakeData.Tail.x += snakeData.Field[snakeData.Head.x][snakeData.Head.y].dx;
snakeData.Tail.y += snakeData.Field[snakeData.Head.x][snakeData.Head.y].dy;
}
//Move Head
snakeData.Head.x += snakeData.dx;
snakeData.Head.y += snakeData.dy;
//Draw Head
SetCursor(snakeData.Head.x, snakeData.Head.y);
cout << "\xCE";
return true;
Here are my structs:
#define WIDTH 30
#define HEIGHT 30
enum FieldTypeT
{
empty,
Snake
};
struct FieldT
{
FieldTypeT fieldType;
int dx;
int dy;
};
struct PointT
{
int &x;
int &y;
};
struct SnakeDataT
{
PointT Head;
PointT Fruit;
int &dx;
int &dy;
PointT Tail;
FieldT Field[WIDTH][HEIGHT];
};
If you need more Insight I'll add what you need.
Bear with me though, the Teacher is asking for questionable practices.