lightshow.c

#include <stdio.h>
#include <stdlib.h>
#include <wiringPi.h>
#include <unistd.h>

typedef struct
{
  int num;
  int state;
} Pin;

Pin * each_pin (int pinc, Pin pins[], Pin (*fun)(Pin, int))
{
  int i;
  Pin p;
  for (i=0;i<pinc;i++) {
    p = pins[i];
    pins[i] = (*fun)(p, i);
  }

  return pins;
}

Pin print_pin(Pin p, int idx)
{
  printf("The pin is %i\n", p.num);
  return p;
}

Pin setup_pin(Pin p, int idx)
{
  int new_state = (idx % 2 == 0) ? HIGH : LOW;
  printf("Setting up GPIO %i as OUTPUT\n", p.num);
  pinMode(p.num, OUTPUT);
  p.state = new_state;
  digitalWrite(p.num, p.state);
  return p;
}

Pin flip_pin(Pin p, int idx)
{
  p.state = (p.state == HIGH) ? LOW : HIGH;

  digitalWrite(p.num, p.state);
  return p;
}

Pin make_pin(num)
{
  Pin p = {num, LOW};
  return p;
}

int main (int argc, char *argv[])
{
  int pinc = argc - 1;
  Pin pins[argc];

  int i;
  for (i=1; i < argc; i++)
  {
    char *arg = argv[i];
    pins[i-1] = make_pin(atoi(arg));
    printf("Arg is %s\n", arg);
  }

  printf("Arg1 is %i", atoi(argv[1]) );

  wiringPiSetup();

  each_pin(pinc, pins, &print_pin);
  each_pin(pinc, pins, &setup_pin);

  for (;;)
  {
    each_pin(pinc, pins, &flip_pin);
    usleep(300000);
  }

  return 0;
}