Your code works fine, but i am finding it hard to tun it with the If comando.
Listed code below will allways print the c value when executing the if comando. It will never see p as greater then c.
Something i am missing ?
void loop() {
float c = analogRead(analogPin0) * 0.00491;
lcd.cursorTo(1,6);
printDouble(c,2);
if (c > p){
lcd.cursorTo(1,16);
printDouble(c,2);
float p = c;
}