#include <stdio.h>    /* for getchar, ungetc, stdin, EOF */
#include <stdlib.h>   /* for malloc, realloc, free, size_t */
#include <ctype.h>    /* for isspace */

int main(int argc, char **argv)
{
	size_t n;
	char *p;

	for (p = malloc(n = 1);; p = realloc(p, ++n)) {
		int c;
		if (p == NULL) {
			fprintf(stderr, "%s: out of store\n", argv[0]);
			return EXIT_FAILURE;
		}

		if ((c = getchar()) == EOF) {
			break;
		}

		if (isspace((unsigned char)c)) {
			ungetc(c, stdin);
			break;
		}

		p[n - 1] = c;
	}
	p[n - 1] = '\0';

	printf("The word \"%s\" was terminated by the ", p);
	if (feof(stdin)) {
		printf("end of file.\n");
	} else {
		printf("whitespace character '\\x%02x'.\n",
			(unsigned char)getchar());
	}
	
	free(p);
	return feof(stdin) && !ferror(stdin) ? EXIT_SUCCESS : EXIT_FAILURE;
}