Q: I'd like to write a helper function and declare a prototype for it, but am I allowed to modify the .h file to do so?: A: Function prototypes don't have to go in a .h file. Declare them near the top of your .cpp file and it will work fine.
Q: The spec says that I need to throw an exception in certain cases. But it looks like the provided main program never goes into those cases; it checks for that case before ever calling my function. Doesn't that mean the exception is useless? Do I actually have to do the exception part?: A: The exception is not useless, and yes you do need to do it. Understand that your code might be used by other client code other than that which was provided. You have to ensure that your function is robust no matter what parameter values are passed to it. Please follow the spec and throw the exceptions in the cases specified.
Q: Is the Sierpinski code supposed to be slow when I put in a large, value for N like 15?: A: Yes; keep in mind that the program is drawing roughly 3¹⁵ triangles if you do that. That is a lot of triangles. We aren't going to test you on such a high order fractal.
Q: Are the Sierpinski triangles supposed to exactly overlay each other? Mine seem to be off by ~1 pixel sometimes.: A: The off-by-one aspect is because the triangle sizes are rounded to the nearest integer. You don't have to worry about that, as long as it is only off by a very small amount such as 1 pixel.
Q: Is the flood fill code supposed to paint so slowly?: A: Yes; the Stanford graphics library has poor graphics performance.
Q: When I run the sample solution, the flood fill pixels paint in a certain order. Does my function need to fill in that same order?: A: No; the order the pixels are filled does not matter, as long as you fill the right pixels.
Q: What does it mean if my program "unexpectedly finishes"?: A: It might mean that you have infinite recursion, which usually comes when you have not set a proper base case, or when your recursive calls don't pass the right parameters between each other. Try running your program in Debug Mode (F5) and viewing the call stack trace when it crashes to see what line it is on when it crashed. You could also try printing a message at the start of every call to make sure that you don't have infinite recursion.
If you are certain that you do not have infinite recursion, it is possible that there are just too many calls on the call stack because you are filling a very large area of the screen. If you tried to fill the whole screen with the same color, it might crash with a "stack overflow" even if your algorithm is correct. This would not be your fault.
Q: Can I use one of the STL containers from the C++ standard library?: A: No.
Q: I already know a lot of C/C++ from my previous programming experience. Can I use advanced features, such as pointers, on this assignment?: A: No; you should limit yourself to using the material that was taught in class so far.
Q: Can I add any other files to the program? Can I add some classes to the program?: A: No; you should limit yourself to the files and functions in the spec.