/* -*- compile-command: "gcc -g rail.c -o rail -lm" -*- */

/**
 * rail.c -- Simple transposition cipher
 * Time-stamp: "2006-10-15 15:09:11 ghoseb"
 */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <math.h>

#define MESSAGE "WEAREDISCOVEREDFLEEATONCE"

int main(int argc, char *argv[])
{
        int len = strlen(MESSAGE);
        int row = 3;
        int column = abs(ceil (len/(float)row));
        int i, j, k;
        int index = 0;
        char **fence;
        
        char *str = (char *)malloc(sizeof(MESSAGE));
/*         char *cipher = (char *)malloc(sizeof(MESSAGE)); */
        
        strcpy(str, MESSAGE);

        for (i=0; i<row; i++) {
                fence[i] = (char *)malloc(column * sizeof(char));
                for (j=0; j<column; j++) {
                        index = i+(row*j);
                        if (index < len) {
                                fence[i][j] = str[index];
                        } else {
                                fence[i][j] = 'X';
                        }
                }
        }

        /*
          str now contains the cipher text
        */
        k = 0;
        for (i=0; i<row; i++) {
                for (j=0; j<column; j++) {
                        str[k] = fence[i][j];
                        k++;
                }
        }

        printf ("%s\n", str);
        return 0;
}