ATX2 use Maximum value from zx-sound displayed on bargraph

#include <ATX2.h>
int y,i;
long x;
void setup(){
  glcdMode(1);
  setTextSize(3);
}
void loop(){
   x=0;
  // for (i=0;i<100;i++){x=analog(0)+x;}
  // x=x/100;
  // use Maximum Value show on Bargraph
   for (i=0;i<100;i++){x=max(analog(0),x);delay(1);}
   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);
}