Beginners Serial input problem

i having trouble getting program wait key board input.

task use arduino uno output pwm waveform hardware , wait whilst make measurements. plan send serial byte (any byte) move on, increase pwm value predefined increment , repeat until max value of 255 reached.

the first wait loop wait1 working , can start program, wait until enter stepsize gets stuck in wait2 loop.

please can point me why code not work please.

tia

when enter stepsze2, serial window shows:

enter step size 1-9 step size =2
value 0


my code is

int val=0;
int stepsize=1;
int dummy=0;
void setup() {

  serial.begin(9600);   // opens serial port, sets data rate 9600 bps
  serial.print ("enter step size 1-9 ");
wait1:
  if (serial.available()==0) {
    goto wait1;//wait key press
  }
  stepsize=serial.read()-48;//convert ascii number
  serial.print("step size =");
  serial.println(stepsize,dec);
  serial.print ("value ");
  serial.println(val,dec);
next:
  {
    analogwrite(9,val);
    serial.flush();// might not needed?
wait2:
    if (serial.available()==0) {
      goto wait2; //wait key press  <<<code gets stuck here
    }
    dummy=serial.read();// used read input buffer don't use data
    val=val+stepsize;
    if (val<=255) {
      goto next;
    }
  }
}

void loop() {
}

this not basic. ditch stupid gotos , labels.

code: [select]

   while(serial.available() == 0)
   {
      // nothing
   }

where assign value val? why expect contain other 0?

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