/*  Continents.swift (c) Kari Laitinen

    http://www.naturalprogramming.com

    2016-11-05 File created.  2018-03-17 Last modification.

    This program shows how some common String methods work.

      - index() returns an index which is of type String.Index.
        Swift strings cannot be indexed with values of type Int.
      - range( of: ) can tell where another string is located 
        within a string
      - subscripting can take a substring in the specified range.
      - prefix( upTo: ) returns a substring taken from the beginning.
      - suffix( from: ) returns a substring from the end of a string.
      - replacingOccurrences( of:, with: ) replaces substrings.
      - uppercased() returns a string in which all letters are converted
        to upper case if necessary.
*/

import Foundation

let indexes =         "01234567890123456789012345678901234567890123456"
let continent_names = "America Europe Africa Asia Australia Antarctica"

print( "\n   "  +  indexes  )
print( "   "  +  continent_names  +  "\n" )

let index_of_9th_character = 
      continent_names.index( continent_names.startIndex, offsetBy: 8 )

print( "   \( continent_names[ index_of_9th_character ] )" )

let range_of_first_ia = continent_names.range( of: "ia" )

let index_of_first_ia : Int =

         continent_names.distance( from: continent_names.startIndex,
                                     to: range_of_first_ia!.lowerBound ) 

print( "   \( index_of_first_ia )" )

//  It seems that there is no Swift method that would correspond with the
//  method lastIndexOf() that exists in many programming languages.

let range_of_atlantis = continent_names.range( of: "Atlantis" )

if range_of_atlantis == nil
{
   print( "   Atlantis is not a known continent." )
}

let lower_bound_of_substring = continent_names.index( 
                                     continent_names.startIndex, offsetBy: 15 )
let upper_bound_of_substring = continent_names.index(
                                     continent_names.startIndex, offsetBy: 26 )

let range_of_substring = lower_bound_of_substring ..< upper_bound_of_substring

let substring_15_26 = continent_names[ range_of_substring ] 

print( "   " + substring_15_26 )

let substring_0_27 = continent_names.prefix(
         upTo: continent_names.index( continent_names.startIndex, offsetBy: 27 ) )

print( "   " + substring_0_27 )

let substring_from_27_to_end = continent_names.suffix(
       from: continent_names.index( continent_names.startIndex, offsetBy: 27 ) )

print( "   " + substring_from_27_to_end + substring_0_27 )

print( "   " + continent_names.replacingOccurrences( of: "ica", with: "XXX" ) )

print( "   " + continent_names.uppercased() + "\n" )