Question

Can you please produce the Java code that solves this non-assessed homework problem? I'm very new to Java and Object-Oriented Programming and I have no idea how to construct the logic for this code.

PROBLEM:

"In this exercise, you will build a program that determines the validity of a select few simple English sentences, according to rules detailed below. A sentence will be represented as an array of words, which you will create as a static nested class `Word`.

`Word` is a good candidate for a static nested class, because every sentence (except the empty sentence) contains at least one word. Furthermore, the Word class does not have much use apart from checking the validity of sentences.

Create a class `Sentence` with an instance variable `public Word[] words`.

Furthermore:
* The class should have a constructor `Sentence(int size)`, where `size` determines the length of the `sentence` field of a given Sentence.
* The class should have an instance method `public boolean isValid()` that determines the validity of a sentence according to the rules detailed below.
* You may add as many more methods as you require.

Also create a public static nested class `Word`, with instance variables `String word` and `Type type`.

Within this class, you must create:
* A public enum type `Type` that contains `NOUN`, `ADJECTIVE`, and `VERB`.
* The constructor Word(String value, Type type).

RULES FOR SENTENCE VALIDITY:

1. A sentence must have a length of at least 1.
2. A NOUN must be followed by a VERB (unless it is at the end of a sentence).
3. An ADJECTIVE must be followed only by another ADJECTIVE or a NOUN.
4. A sentence must have one and only one VERB.
5. A sentence must end in a NOUN or in a VERB."

Answer 1

Here is the completed code for this problem. Comments are included, go through it, learn how things work and let me know if you have any doubts or if you need anything to change. If you are satisfied with the solution, please rate the answer. Thanks

// Sentence.java

public class Sentence {

      private Word[] words; // array of words constituting a sentence

      private int count; // current number of words added

      public Sentence(int size) {

            // initializing words list

            words = new Word[size];

            count = 0; // current length

      }

      // method to check if sentence is valid or not

      public boolean isValid() {

            if (count == 0) {

                  // empty sentence

                  return false;

            }

            // variable to store count of verbs

            int countVerbs = 0;

            // looping through words in sentence

            for (int i = 0; i < count; i++) {

                  // checking if current word is NOUN

                  if (words[i].type == Type.NOUN) {

                        // checking if there exists a next word

                        if ((i + 1) < count) {

                              // next word should be a VERB

                              if (words[i + 1].type != Type.VERB) {

                                    // not a VERB, invalid

                                    return false;

                              }

                        }

                  } else if (words[i].type == Type.ADJECTIVE) {

                        // ADJECTIVE should be followed by a NOUN or ADJECTIVE

                        if ((i + 1) < count) {

                              if (words[i + 1].type != Type.ADJECTIVE

                                           && words[i + 1].type != Type.NOUN) {

                                    // other then adjective or noun

                                    return false;

                              }

                        } else {

                              // no next word.

                              return false;

                        }

                  } else if (words[i].type == Type.VERB) {

                        // incrementing verbs count

                        countVerbs++;

                        if (countVerbs > 1) {

                              // more than 1 VERB found

                              return false;

                        }

                  }

            }

            // checking word ends with NOUN or VERB

            if (words[count - 1].type != Type.NOUN

                        && words[count - 1].type != Type.VERB) {

                  // it doesnt.

                  return false;

            }

            // all checks completed. valid

            return true;

      }

      // method to add a word to the sentence, returns true if added, else false

      public boolean addWord(Word word) {

            if (count < words.length) {

                  words[count] = word;

                  count++;

                  return true;

            }

            return false; // full

      }

      // Word class

      private static class Word {

            String word;

            Type type;

            public Word(String value, Type type) {

                  this.word = value;

                  this.type = type;

            }

      }

      // enum Type

      public enum Type {

            NOUN, ADJECTIVE, VERB;

      }

      // just a tester program

      public static void main(String[] args) {

            Sentence sentence = new Sentence(4);

            // I dont know much about the grammar and all, just checking if the

            // isValid method is working correctly, just mind only the Type, and not

            // the words.

            sentence.addWord(new Word("Java", Type.NOUN));

            sentence.addWord(new Word("is", Type.VERB));

            sentence.addWord(new Word("beautifully", Type.ADJECTIVE));

            sentence.addWord(new Word("made", Type.NOUN));

            System.out.println(sentence.isValid()); //should be true

      }

}

/*OUTPUT*/

true