//
// Program to demonstrate use of lstring class.
//
// Author:  B. Massingill.
//
// Input:  Text strings, two at a time; control-D to end.
//           (Program prompts for these.)
// Output:  Results of applying various string operations
//            to the input strings, using the lstring class.
//

#include <iostream.h>
#include <stdlib.h>		// has EXIT_SUCCESS
#include <ctype.h>		// has toupper()
#include "lstring.h"

int main(void) {

  // Several ways to declare and initialize lstrings.

  lstring empty;		// empty lstring.
  lstring one_char('a');	// lstring built from one char.
  lstring some_chars("abcd");	// lstring built from C-style string.

  // Stream output works on lstrings.

  cout << "Empty string = " << empty << endl;
  cout << "One-character string = " << one_char << endl;
  cout << "Multi-character string = " << some_chars << endl;

  // empty() member function returns true if empty, false otherwise.

  cout << "Is empty string empty?  ";
  if (empty.empty())
    cout << "yes\n";
  else
    cout << "no\n";

  lstring s1, s2;

  char prompt[] = "Enter two strings s1 and s2, or control-D to end:\n";

  cout << prompt;

  // Stream input works on lstrings.

  while (cin >> s1 >> s2) {

    cout << "You entered:  " << s1 << " and " << s2 << endl;

    // s.empty() is true if s is empty, false otherwise.

    if (s1.empty())
      cout << "s1 is empty\n";
    if (s2.empty())
      cout << "s2 is empty\n";

    // s.length() is the length of s.

    cout << "Length of s1 is " << s1.length() << endl;
    cout << "Length of s2 is " << s2.length() << endl;

    // Relational operators work on lstrings (lexicographic
    //   comparison, as with C++ strings).

    if (s1 == s2)
      cout << "s1 == s2\n";
    if (s1 != s2)
      cout << "s1 != s2\n";
    if (s1 <= s2)
      cout << "s1 <= s2\n";
    if (s1 >= s2)
      cout << "s1 >= s2\n";
    if (s1 < s2)
      cout << "s1 < s2\n";
    if (s1 > s2)
      cout << "s1 > s2\n";

    // s.find(t) is true if t is found in s (i.e., t is a
    //   substring of s), false otherwise.

    if (s1.find(s2))
      cout << "s2 found in s1\n";
    if (s2.find(s1))
      cout << "s1 found in s2\n";

    // s.getElementAt(i) is the i-th character of s.
    // lstring::length_pos is the data type used in lstring
    //   for lengths and positions.

    for (lstring::length_pos i = 0; i < s1.length(); ++i) 
      cout << "element " << i << " of s1 is " 
	   << s1.getElementAt(i) << endl;

    // s.replaceElementAt(j, c) replaces the j-th character of s
    //   with c.  
    // here we use it to translate an lstring to all uppercase.

    for (lstring::length_pos j = 0; j < s2.length(); ++j)
      s2.replaceElementAt(j, static_cast<char>(toupper(s2.getElementAt(j))));
    cout << "s2 in upper case is " << s2 << endl;

    // "+" for lstrings is concatenation.

    cout << "s1 plus s2 is " << s1 + s2 << endl;

    // s.append(t) appends t to s.

    cout << "appending 'abcd' to s1....\n";
    s1.append(empty);
    s1.append(some_chars);
    cout << "result is " << s1 << endl;

    // s.insertBefore(t, i) inserts t into s before the i-th
    //   character.  (If i is s.length(), this is the same as
    //   appending t to s.)

    cout << "inserting empty string into s2 several times....\n";
    s2.insertBefore(empty, 0);
    s2.insertBefore(empty, s2.length());
    s2.insertBefore(empty, 1);
    cout << "result is " << s2 << endl;

    cout << "inserting 'abcd' at start of s2....\n";
    s2.insertBefore(some_chars, 0);
    cout << "result is " << s2 << endl;
    cout << "inserting 'abcd' at end of s2....\n";
    s2.insertBefore(some_chars, s2.length());
    cout << "result is " << s2 << endl;
    cout << "inserting 'abcd' into s2 before character " 
	 << s2.length()/2 << "....\n";
    s2.insertBefore(some_chars, s2.length()/2);
    cout << "result is " << s2 << endl;

    cout << prompt;
  }

  return EXIT_SUCCESS;
}