read serial character in arduino

serial_rw.pde

#include <stdio.h>

char cmd;

#define CMD_ROCK 'r'
#define CMD_PAPER 'p'
#define CMD_SCISSORS 's'

void setup() {
  Serial.begin(9600);
}

void loop() {
  while (Serial.available()) {
    cmd = Serial.read();
    got_command(cmd);
  }
}

void got_command(char cmd) {
  switch (cmd) {
    case CMD_ROCK:
      // got rock!
      break;
    case CMD_PAPER:
      // got paper!
      break;
    case CMD_SCISSORS:
      // got scissors!
      break;
  }
}