lab09b
Pig La(b)tin I

For the following problems, remember that to extract the character at index i from a String s, you can either say s.charAt(i) (which returns a char), or s.substring(i,i+1) (which returns a String-of-length-1). Also, remember that to compare two Strings, use equals.

Make a class VowelExpert, with a method firstA. This method takes in a String and returns the index of the first time an upper- or lower-case letter 'A' occurs. If the input doesn't contain any letter 'a', then return the last valid index plus one.

class TestVowelExpert {
  public static void main( String[] args ) {
    VowelExpert ve = new VowelExpert();

    System.out.println( "Expect 3: " + ve.firstA( "senator" ) );
    System.out.println( "Expect 1: " + ve.firstA( "yahoo!" ) );
    System.out.println( "Expect 0: " + ve.firstA( "Aardvark" ) );
    System.out.println( "Expect 4: " + ve.firstA( "huh?" ) );
    // Some corner cases:
    System.out.println( "Expect 3: " + ve.firstA( "yoga" ) );
    System.out.println( "Expect 0: " + ve.firstA( "a" ) );
    System.out.println( "Expect 1: " + ve.firstA( "z" ) );
    System.out.println( "Expect 0: " + ve.firstA( "" ) );
    }
  }

Hint: Your loop condition should be something like “while the i'th index is valid, and the i'th character isn't 'A'”. In this case, the index variable and the accumulator variable are actually the same thing!

Make another firstVowel. Note that an easy way to tell if a (one-character-long) String s is a vowel is to call contains: "aeiouAEIOU".contains("x") is false, but "aeiouAEIOU".contains("i") is true.
Challenge: don't have your code repeat the vowels in upper and in lower case. Instead, somehow use toLowerCase…
Challenge (optional): Write a single method firstCharFrom, which takes in two Strings: the word to search (as usual), plus a String of letters to search for (e.g. firstCharFrom("dyslexic quack","qxz") returns 5, because the character at index 5 ('x') occurs inside "qxz".

Once you have this method working, you can replace both of the above functions with single-line calls to firstCharFrom.
Write a method which takes in a single word, and converts it to pig latin. (Ta-dum!)

Do this by calling your previous method firstVowel¹ using the result to decide which substrings to take from your input word.

(To think about: what does your method do, if the input contains no vowels at all?)

(For how to slice together substrings, recall also the solution to left2 on hw05-soln.html.)

¹ How do you have one of your own methods call another? The same way we've always called methods: “object - dot - methodname - paren -arguments”. The question is, what to use for that first “object -dot”?

The answer is: use whichever object whose pig-latin method was called; you can do this by using the variable “this”, which always refers to "the object whose method is being called". It's just a regular variable, but one which Java secretly declares and initializes for you in every method. Example: inside pigLatinize, you might write something like “int splitPoint = this.firstVowel(…)”.

Note that if you call a method but you leave off the “object - dot” of then Java secretly writes in “this.” for you. Rather than think “Oh, the object-dot is optional”, I prefer to think “if I don't tell what Java which object I want to use, by default it uses the object whose method we're currently in.”

The variable “this” can't be used in BlueJ's Code Pad: because as you are typing, we're not in the middle of a method-call, so there's no object whose method we're currently in.

↩

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lab09bPig La(b)tin I

lab09b
Pig La(b)tin I