typedef void (*fp)(void); //function pointer

typedef struct
{
  char *command;
  fp    function;
} command_t;

command_t cmd_array[] =
{
  { "START", STARTExecute },
  { "STOP",  STOPExecute  },
  { "DUMP",  DUMPExecute  },
};

i=0;
while (i < sizeof(cmd_array) / sizeof(command_t))
{
  if (strcmp (cmd_array[i].command, rx_buf) == 0)
  {// if the command is found, call the function
    cmd_array[i].function();
  }
}