extraction of intensity maxima minima from hue plane

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i hav extracted the hue information from a rgb image and stored it into a separate image file. now I need to find min and max values present in this image. how do i do that. here is my code do that. what is wrong with it. it throws seg fault. the image I supply to this code is the hue image extracted from the rgb image http://www.pasteall.org/38741/c