ConversationIntro.java

public class ConversationIntro {

  /*
   *  Example A:  plusOne (warmup)
   *  To make sure everything it working, remove the comment
   *  from the line in the method below.  When you have done so,
   *  the program should be able to pass the first test.
   */
  
  /** Returns an integer one larger than its input */
  public int plusOne(int n) {
    // n = n+1;
    return n;
  }

  /*
   *  Exercise 1:  timesTwo
   *  Here's a function similar to the one above.
   *  See if you can figure out how to make it work.
   */
  
  /** Returns an integer that is double its input */
  public int timesTwo(int n) {
    return 0;
  }

  /*
   *  Exercise 2:  squared
   */
  
  /** Returns the square of its input */
  public int squared(int n) {
    return 0;
  }

  /*
   *  Exercise 3:  integer division
   */
  
  /** Divides its input by seven, dropping remainders */
  public int intDivideBy7(int n) {
    return 0;
  }

  /*
   *  Exercise 4:  double precision floating point division
   */
  
  /** Divides its input by 7 */
  public double doubleDivideBy7(int n) {
    return 0;
  }

  /*
   *  Example B:  isPrime
   *  
   *  This function is completely written for you.
   *  Uncomment the loop to make it work, examining it as you do so.
   *  It contains an example of a loop, and also 
   *  the % operator, which computes the integer remainder
   */
  
  /** Returns true if its input is prime */
  public static boolean isPrime(int n) {
    boolean isPrime = (n > 1); // one, zero, and negatives not prime
    /*for (int i = 2; i <= Math.sqrt(n); i++) {
        if (n%i == 0) {
            isPrime = false;
        }
    }*/
    return isPrime;
  }

  /*
   *  Exercise 5:  isEven
   */
  
  /** Returns true if its input is even */
  public boolean isEven(int n) {
    return false;
  }

  /*
   *  Example C:  isComma
   *  
   *  Now we move to string processing.
   *  This function is meant to perform a string comparison
   *  but as written it uses the wrong equality test for strings.
   *  Replace the comparison with the commented line to make 
   *  it work properly.
   */
  
  /** Returns true if its input is a comma */
  public static boolean isComma(String s) {
    //return s.equals(",");
    return (s == ",");
  }

  /*
   *  Exercise 6:  isPunctuation
   */
  
  /** Returns true if its input is one of:  .,?! */
  public boolean isPunctuation(String s) {
    return false;
  }

  /*
   *  Exercise 7:  mirrorWord
   */
  
  /** Returns its input, unless it is "I" or "you", which switch */
  public String mirrorWord(String s) {
    return s;
  }

  /*
   *  Example D:  wholeNumbers
   *  
   *  This example shows the use of a loop to put
   *  values into an array.  Uncomment the loop to
   *  make the example work.
   */
  
  /** Returns an array of whole numbers up to n */
  public static int[] wholeNumbers(int n) {
    int[] arr = new int[n]; // allocate space for the array
    //for (int i = 0; i < n; i++) {
    //  arr[i] = i+1;
    //}
    return arr;
  }

  /*
   *  Exercise 7:  squares
   *  Write a loop here to match the description
   */
  
  /** Returns an array of squares from 1 to n*n */
  public static int[] squares(int n) {
    int[] arr = new int[n]; // allocate space for the array
    return arr;
  }
}