title: Image bounds checking with unsigned numbers
body: <p>I have an image represented by 2D matrix indexed by size_t. I wan't to have a function that you give a position and it returns if that position is inside the bounds of that image.</p>
  
  <p>Where I would use such function, is f.e. in floodfill algorithm where I would after checking one pixel, push it's surrounding 4 pixels into the queue. Problem occurs if the pixel I'm checking is on 0 x or y which means the inBounds function would get called with (x - 1, y) and (x, y - 1). Because of size_t being unsigned I can't reasonably check if the x or y is &lt; 0.</p>
  
  <p>How can I deal with these situations? Should I just check for bottom and left bound and assume that if given position is above or to the right of image it will be huge number anyway?</p>