lcd.begin(16, 2);{
Why is that curly brace there?
if( Serial.available() ) // if data is available to read
{;}
If there is data to read, do nothing. Otherwise, no nothing. Why?
val = Serial.read(); // read it and store it in 'val'
Even if there isn't any. Why?
if( val =='z' )
buzz(10, 700, 500);
void buzz(int targetPin, long frequency, long length) {
long delayValue = 1000000/frequency/2;
long numCycles = frequency * length/ 1000;
You can't have code that is not in a function.