/*
 *  ce -- center text
 *  $ cc -O2 -o ce ce.c
 */

#include <err.h>
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAXBUF 255

int
main(int argc, char *argv[])
{
	char *buf;
	int cols, i, max;

	if(argc-1 > 1){
		fprintf(stderr, "usage: %s [cols]\n", argv[0]);
		return 1;
	}
	cols = argv[1] ? atoi(argv[1]) : 80;

	if(!(buf = malloc(MAXBUF)))
		err(1, "malloc");

	while(fgets(buf, MAXBUF, stdin)){
		buf[strcspn(buf, "\n")] = 0;

		/* Remove leading and trailing whitespace. */
		for (; *buf; buf++)
			if(!isspace(*buf)) break;
		for (i = strlen(buf)-1; i >= 0; i--)
			if(!isspace(buf[i])) break;
		buf[i+1] = 0;

		/* Calculate number of spaces. */
		max = cols/2 + strlen(buf)/2;

		printf("%*s\n", max, buf);
	}
}