Some String-related stuff

Here are some methods on Java's String class that you might find useful in completing your Igpay assignment. These are all documented in the Java API:

1. .length() gives you the length of a String. So this code:
   String coolProf = "Stephen"; System.out.println(coolProf.length());
   will print

   7
   

   to the screen.
2. .substring(m,n) gives you the characters at position m through n-1 (not n, mind) of the String. So this code:
   String coolPsychopath = "KyloRen"; System.out.println(coolPsychopath.substring(2,5));
   will print

   loR
   

   to the screen. (Not "loRe", as you might expect.)
3. .charAt(n) gives you the single character (as a Character, not a String) at position n. So this code:
   String elvenWarrior = "Galadriel"; Character c = elvenWarrior.charAt(2); System.out.println("There's a " + c + " at position 2");
   will print

   There's a l at position 2
   

   to the screen.
4. .indexOf() is kind of like a "reverse .charAt()": it will return the index of the (first) occurrence in the String of the character passed. So this code:
   String name = "Galadriel"; System.out.println("The first l is at index " + name.indexOf('l'));
   will print

   The first l is at index 2
   

   to the screen. (If you pass an int as a second argument to this function, it will begin at that point instead of at the beginning. So in the above example, "name.indexOf('l',3)" will return 8, not 2.)
5. The function (static method) Character.isUpperCase(x) will return true if x is an upper-case character, and false otherwise. So Character.isUpperCase("B") is true, whereas Character.isUpperCase("q") and Character.isUpperCase("?") are both false. (Similar behavior for Character.isLowerCase(x).)
6. .replace(x,y) will replace all instances of the substring x in a string to the substring y. For instance, this code:
   String pokemon = "Jigglypuff"; String revised = pokemon.replace("g","weird"); System.out.println(revised);
   will print

   Jiweirdweirdlypuff    
   

   to the screen.
7. .split(x) will divide a String into pieces, breaking it on every occurrence of the substring x. It returns an array of the pieces. For instance, this code:
   String pokemon = "Charmander"; String[] pieces = pokemon.split("a"); for (String piece : pieces) { System.out.println("Here's a piece: " + piece); }
   will print

   Here's a piece: Ch
   Here's a piece: rm
   Here's a piece: nder
   

   to the screen.
8. .contains(x), .startsWith(x) and .endsWith(x) tell you whether a String has another String as a substring at the beginning, at the end, or anywhere. So this code:
   String feeling = "heebeejeebees"; System.out.println(feeling.contains("ee")); System.out.println(feeling.startsWith("ee")); System.out.println(feeling.endsWith("bees"));
   will print

   true
   false
   true
   

   to the screen.
9. .toLowerCase() will return a lower-cased version of a string, with non-alphabetic characters unchanged. So this code:
   String message = "What on Earth are you TALKING about, Dude?"; System.out.println(message.toLowerCase());
   will print

   what on earth are you talking about, dude?
   

   to the screen. (And similar for .toUpperCase().)