#include "library.h"

const string jumble = "ldzbwrjnhuagpcxfksemqvtyio";
const string alpha = "abcdefghijklmnopqrstuvwxyz";

int posof(const char c, const string s, const int i)
{ if (i > 25)
    return -1;
  if (s[i] == c)
    return i;
  return posof(c, s, i+1); }

int posof(const char c, const string s)
{ return posof(c, s, 0); }

char encrypt(const char c)
{ const int p = posof(c, jumble);
  if (p == -1)
	return '?';
  return alpha[p]; }

char decrypt(const char c)
{ const int p = posof(c, alpha);
  if (p == -1)
	return '?';
  return jumble[p]; }

string doencrypt(const string s, const int pos)
{ if (pos >= s.length())
    return "";
  const char first = encrypt(s[pos]);
  const string rest = doencrypt(s, pos+1);
  const string result = "";
  return result + first + rest; }

string dodecrypt(const string s, const int pos)
{ if (pos >= s.length())
    return "";
  const char first = decrypt(s[pos]);
  const string rest = dodecrypt(s, pos+1);
  const string result = "";
  return result + first + rest; }

string encrypt(const string s)
{ return doencrypt(s, 0); }

string decrypt(const string s)
{ return dodecrypt(s, 0); }

void main()
{ const string query = read_string();
  const string result = encrypt(query);
  cout << query << " encrypted is " << result << "\n";
  const string orig = decrypt(result);
  cout << result << " decrypted is " << orig << "\n";
  main(); }