/// <summary>
/// HasValidExit determines if a GridPoint on the grid has a valid exit and
/// returns true if it does.
/// When the last square has been set, this method should return false.
/// </summary>
/// <param name="gridPoint">the GridPoint to check exits from</param>
/// <returns>true if a valid exit exists, otherwise false</returns>
private bool HasValidExit(GridPoint gridPoint)
{
//Test up
GridPoint newPoint = new GridPoint(gridPoint.Row, gridPoint.Column);
newPoint.Move(GridPoint.Direction.UP);
if ((IsValid(newPoint)) && (UnionPossible(gridPoint, newPoint)))
{
return(true);
}
//Test down
newPoint = new GridPoint(gridPoint.Row, gridPoint.Column);
newPoint.Move(GridPoint.Direction.DOWN);
if ((IsValid(newPoint)) && (UnionPossible(gridPoint, newPoint)))
{
return(true);
}
//Test left
newPoint = new GridPoint(gridPoint.Row, gridPoint.Column);
newPoint.Move(GridPoint.Direction.LEFT);
if ((IsValid(newPoint)) && (UnionPossible(gridPoint, newPoint)))
{
return(true);
}
//Test right
newPoint = new GridPoint(gridPoint.Row, gridPoint.Column);
newPoint.Move(GridPoint.Direction.RIGHT);
if ((IsValid(newPoint)) && (UnionPossible(gridPoint, newPoint)))
{
return(true);
}
return(false);
}
/// <summary>
/// ValidDirection determines if a randomly generated direction from the
/// initial starting GridPoint is valid, and if the new GridPoint found there can
/// be connected (union) with the initial GridPoint.
/// </summary>
/// <param name="randomNumber">a random number generated to choose direction</param>
/// <param name="gridPoint">the GridPoint to choose a direction from</param>
/// <returns>the new GridPoint object if it is valid, otherwise null</returns>
private GridPoint ValidDirection(int randomNumber, GridPoint gridPoint)
{
//Initialises newPoint to the value of GridPoint
GridPoint newPoint = new GridPoint(gridPoint.Row, gridPoint.Column);
//Moves the new GridPoint in a direction, depending upon which random
//direction is indicated
if (randomNumber == 0)
{
newPoint.Move(GridPoint.Direction.UP);
}
else if (randomNumber == 1)
{
newPoint.Move(GridPoint.Direction.RIGHT);
}
else if (randomNumber == 2)
{
newPoint.Move(GridPoint.Direction.DOWN);
}
else if (randomNumber == 3)
{
newPoint.Move(GridPoint.Direction.LEFT);
}
else
{
Console.WriteLine("Error in random number");
return(null);
}
//If the new GridPoint is valid, and union is possible with the first GridPoint
//return the new GridPoint
if ((IsValid(newPoint)) && (UnionPossible(gridPoint, newPoint)))
{
return(newPoint);
}
return(null);
}
/// <summary>
/// GetDirection gets the direction to another point which is assumed to
/// be at perpendicular offset from this object.
/// </summary>
/// <param name="target">the target GridPoint to compare with</param>
/// <returns></returns>
public GridPoint.Direction GetDirection(GridPoint target)
{
if (target.row < row)
{
return(Direction.UP);
}
else if (target.row > row)
{
return(Direction.DOWN);
}
else if (target.col < col)
{
return(Direction.LEFT);
}
else if (target.col > col)
{
return(Direction.RIGHT);
}
else
{
return(Direction.ERROR);
}
}
/// <summary>
/// IsValid returns if a GridPoint is within the limits of the grid.
/// </summary>
/// <param name="p">a grid point</param>
/// <returns>true if within the grid limits, false if not</returns>
private bool IsValid(GridPoint p)
{
return(p.Row >= 0 && p.Row < maxRows && p.Column >= 0 && p.Column < maxColumns);
}
/// <summary>
/// GetSquareId gets the integer id of a grid square from the row and
/// column of a GridPoint.
/// </summary>
/// <param name="p">a grid point object</param>
/// <returns>an integer id representing square position</returns>
private int GetSquareId(GridPoint p)
{
return(p.Row * maxColumns + p.Column);
}
