Chess Validation Move input wanted - c++

Question

So, I have gotten quite far in my mission to finish a chess game in c++. However, I have hit a bit of a small issue I would like to get some input on, please.
SITUATION:
My PAWN, KING, KNIGHT move validations work perfect. But;
When moving a piece(such as a white ROOK) it follows most of the rules. For example, it will only move vertical or horizontal, it will not pass another white piece, it will not replace a white piece, and lastly it WILL replace a black (opposing) piece.
The problem is when moving it past a another black piece, it allows passing in order to replace a piece that's past it. So lets say we have a white piece at x=2,y=6 and black piece at x=2,y=4, and another black piece at x=2,y=3. The White piece will be allowed to move to move to x=2,y=3, which should not be allowed. Would love to get some input on how to fix this. Current code below.
bool Rook:: canMove(int startx, int starty, int endx, int endy)
{
int i;
if(board[endx][endy] !=NULL && board[endx][endy]->color==color)
return false;
if (startx == ends) //Collision Detection...
{
// Horizontal move
if (starty < endy)
{
// Move down
for (i = starty + 1; i <= endy; ++i)
if (board[startx][i] != NULL && board[startx][i]->color==color)
return false;
}
else
{
// Move up
for (i = starty - 1; i >= endy; --i)
if (board[startx][i] != NULL && board[startx][i]->color==color) //cant allow passing of non color piece
return false;
}
}
else if (starty == endy)
{
// Vertical move
if (startx < endx)
{
// Move right
for (i = startx + 1; i <= endx; ++i)
if (board[i][starty] != NULL && board[i][starty]->color==color)
return false;
}
else
{
// Move left
for (i = startx - 1; i >= endx; --i)
if (board[i][starty] != NULL && board[i][starty]->color==color)
return false;
}
}
else
{
// Not a valid rook move (neither horizontal nor vertical)
return false;
}
return true;
}

Answer 1

your function has refers to a lot of member variables in the class, e.g. ends, color, board, which isn't good, and makes the function hard to test at a unit level
can you test that function standalone? No you can't.
but it looks like your loops aren't breaking when they should (when they have found a valid move perhaps?)
if the function is allowing move to (2,3) as well as (2,4), then it is looping past (2,4) to (2,3)
also, just using an array and ints for indexing the board isn't very good.
i would have expected a higher-level board class and maybe a coordinate class so you can easily iterate and index the board.