#include <stdlib.h> 	// For atoi
#include <stdio.h>  	// For printf and putchar
#include <assert.h>	// For assert

int 	SIZE;
#define SPACING 	((SIZE / 10) + 2)

void reverse(int*, int);

int main (int argc, char **argv)
{
	assert(argc > 1);
	printf("SPACINGS IS %d\n", SPACING);
	SIZE = atoi(argv[1]) + 1;
	int* a = (int*) malloc(sizeof(int) * SIZE);
	int i;
	for(i = 0; i < SIZE; ++i)
		a[i] = i;	
	
	for(i = 0; i < SIZE; ++i)
		printf("%*d ", SPACING, a[i]);
	printf("\n\n");

	reverse(a, SIZE);

	putchar('\n');
	for(i = 0; i < SIZE; ++i)
		printf("%*d ", SPACING, a[i]);
	putchar('\n');

	return 0;
}

void reverse(int* a, int size)
{
	int i, ii, dum;
	for(i = 0; i < size / 2; ++i)
	{		
		dum		= a[i];
		a[i]		= a[size-1-i];
		a[size-1-i]	= dum;

		for(ii = 0; ii < size; ++ii)
			printf("%*d ", SPACING, a[ii]);
		putchar('\n');
	}
}