/* 
	Example: backward printing of text with pointers
	Source: K&R2, p108
	Modified by Peter Brusilovsky
*/

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

#define MAXLINES 5000

static char *lineptr[MAXLINES];

void copy(char *p1, char *p2);
int getline(char *line, int max);
int readlines();
void printbackwards(int n);

void main() {
	int nlines; /* counter of input lines read */
	
	nlines = readlines();
	printbackwards(nlines);
}
	
#define MAXLEN 1000
int readlines()
{
	int len, nlines;
	char *p, line [MAXLEN];
	
	nlines = 0;
	while((len = getline(line, MAXLEN)) > 0) {
		p = (char *) malloc(len+1);
		copy(p, line);
		lineptr[nlines] = p;
		++ nlines;
	}
	return nlines;
}

void printbackwards(int n)
{
	while(n > 0) {
		printf("%s", lineptr[n-1]);
		--n;
	}
}

/* getline: read a line into s,  return length */ 

int getline(char *s, int lim) 
{
	int c, i;

	for (i = 0; i < lim-1 &&(c=getchar())!= EOF && c != '\n'; ++i)
		s[i] = c;
	if (c == '\n') {
		s[i] = c;
		++i;
	}
	s[i] = '\0';
	return i;
}

/* copy: copy 'from' into 'to'; assume to is big enough */
void copy(char *to, char *from)
{
	int i = 0;
	
	while((to[i] = from [i]) != '\0')
		++i;
}