c# - how to move an object through a grid -

i'm having trouble coming solution on how use array snake game. have head 20x20 pixels on 400x400 size window.

areagrid = new vector2[columns, rows];  (int x = 0; x < columns; x++) {     (int y = 0; y < rows; y++)     {         areagrid[x, y] = new vector2(x * 20, y * 20);         console.writeline("areagrid[{0},{1}] = {2}", x, y, areagrid[x, y]);     } } 

so naturally, there 400 "blocks" head of snake plus tail can occupy. have head drawn in array @ [5, 5] coords 100, 100 on grid. want head move 20 pixels @ time new point in array. examply, movement right place head @ [5, 6] in array , @ 120, 100 on grid. dont know how that. how implement movement thru array within update method?

use list block coords:

list<vector2> snake = new list() { {5,5}, {5,6}, {5,7}, {6,7}, {7,7} } 

and render it:

var transform = matrix.createscale(20) * matrix.createtranslation(offset); spritebatch.begin(null,null,..., tranform); foreach (var pos in snake)   spritebatch.draw(white_1x1_texture, pos, null, snakecolor); spritebatch.end(); 

or

spritebatch.begin(); foreach (var pos in snake) {   var box = new rectangle(offset.x + pos.x * 20, offset.y + pos.y*20, 20,20);   spritebatch.draw(white_1x1_texture, box, null, snakecolor); }  spritebatch.end();