/*
 * A simple example to help understand process layout in memory and stack
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

/* BIG is 64KB */
#define	BIG (1 << 16)

char big_array[BIG];
char buffer[BIG] = "I'm a string";
int z = 101;

/*
 * The recursive sumup function
 */
static int
sumup(int x)
{
	int	rval;

	if (x == 0) {
		return (0);
	}

	rval = sumup(x - 1);

	return (x + rval);
}

/*
 * The swap function
 */
static void
swap(int *x, int *y)
{
	int	t;

	t = *x;
	*x = *y;
	*y = t;
}

/*
 * We will force execution of the foo function on returning from swap
 */
int
foo(void)
{
	(void) printf("You called foo()\n");

	return (0);
}

/*
 * Do a few bits and pieces
 */
int
main(int argc, char **argv)
{
	char	local[128];
	int	a, b;
	char	*ptr;

	/* Check usage */
	if (argc != 1) {
		(void) fprintf(stderr, "Usage: %s\n", argv[0]);
		exit(EXIT_FAILURE);
	}

	/* Copy a string */
	(void) strcpy(local, "I am a C program");

	/* Allocate some memory */
	ptr = (char *)malloc(BIG * sizeof (*ptr));

	/* Check allocation succeeded */
	if (ptr == NULL) {
		perror("malloc()");
		exit(EXIT_FAILURE);
	}

	/* Copy another string */
	(void) strcpy(ptr, "I'm going on the heap");

	/* Free memory */
	free(ptr);

	/* Call some functions */
	a = 5;
	b = sumup(a);
	swap(&a, &b);

	return (0);
}