To continue on my explanations of array usage... Once you have figured out pointers you gain a very useful tool. Unfortunately you may still want some of the characteristics of the multi-dimensional array. Currently I'm working on an image manipulation algorithm (though I apply it to sound). The math for the mutation of the image is dependant on the use of an X,Y matrix (two-dimensional array). The problem is how do you perform a manipulation on data within a matrix but store the information in a linear (one-dimensional) array.

        array[10];				// an array with 10 values
        matrix[5][2];				// a matrix with 5 groups of two values
        
        array = {0,1,2,3,4,5,6,7,8,9};
        matrix = {{0,1},{2,3},{4,5},{6,7},{8,9}};
        

to derive (x,y) values from a linear array

        x = linear_value / xmax	//integer division (drop the decimals)
        y = linear_value % ymax
        
        xmax = number of columns
        ymax = number of rows
        % = mod operator, the remainder after division
        
        ex. (using the above array and matrix)
        	array[5] = (x,y)
        	x = 5/2 = 2
        	y = 5%2 = 1 
        	(x,y) = (2,1)

to derive linear values from an (x,y) matrix

	linear_value = (xmax * x) + y