ATX2 Read Average ADC0 show On Bargraph

#include <ATX2.h>
int x,y,i;
void setup(){
  glcdMode(1);
  setTextSize(3);
}
void loop(){
   x=0;
   for (i=0;i<20;i++){x=analog(0)+x;}
   x=x/20;
   y = map(x,0,1023,0,160);
   glcd(1,0,"%d  ",y);
   glcdFillRect(0,80,y,10,GLCD_RED);
   glcdFillRect(y,80,160-y,10,GLCD_BLACK);
}