#include "library.h"

const string alpha = "abcdefghijklmnopqrstuvwxyz ";
const string other = "hzbdowumrjgaqitvenypcskxfl ";

int find(const char c, const string s, const int pos)
{ if (pos >= s.length())
    return -1;
  if (s[pos] == c)
    return pos;
  return find(c, s, pos + 1); }

string encrypt(const string s, const string lookup, const string replacements)
{ if (s == "")
    return "";
  const char c = s[0];
  const int pos = find(c, lookup, 0);
  const char rep = replacements[pos];
  const string empty = "";
  return empty + rep + encrypt(s.substr(1)); }

void main()
{ cout << "Enter a string: ";
  const string s = read_line();
  const string t = encrypt(s, alpha, other);
  cout << "Encrypted = " << t << "\n";
  const string u = encrypt(s, other, alpha);
  cout << "Decrypted = " << u << "\n"; }