CSC300: numFives starter code with array [17/17] Previous pageContents

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package algs13;
import java.text.DecimalFormat;
import stdlib.*;
public class Playground {
  private double a[]; 
  private Node first;
  static class Node { 
    public double item; 
    public Node next; 
    public Node (double item, Node next) { 
      this.item = item; 
      this.next = next; 
    }
  }

  public int numFives () {
    return StdRandom.uniform (100); //TODO: fix this
  }

  /* ToString method to print */
  public String toString () { 
    // Use DecimalFormat #.### rather than String.format 0.3f to leave off trailing zeroes
    DecimalFormat format = new DecimalFormat ("#.###");
    StringBuilder result = new StringBuilder ("[ ");
    for (Node x = first; x != null; x = x.next) {
      result.append (format.format (x.item));
      result.append (" ");
    }
    result.append ("]");
    return result.toString ();
  }

  /* Method to create lists */
  public static Playground of(String s) {
    Playground result = new Playground ();
    if ("".equals (s)) {
      // special case for the empty array
      result.first = null;
      result.a = new double [0];
    } else {
      String[] nums = s.split (" ");
      Node first = null;
      double[] a = new double[nums.length];
      for (int i = nums.length-1; i >= 0; i--) {
        double num = Double.NaN;
        try { 
          num = Double.parseDouble (nums[i]); 
        } catch (NumberFormatException e) { 
          throw new IllegalArgumentException (String.format ("Bad argument \"%s\": could not parse \"nums[i]\" as a double", s, nums[i]));
        }
        a[i] = num;
        first = new Node (num, first);  
      }
      result.a = a;
      result.first = first;
    } 
    return result;
  }

  public static void testNumFives (int expected, String sList) {
    Playground list = Playground.of (sList); 
    int actual = list.numFives ();
    if (expected != actual) {
      StdOut.format ("Failed: Expecting [%d] Actual [%d] with argument %s\n", expected, actual, list);
    }
  }
  public static void main (String[] args) {
    testNumFives (0, "");
    testNumFives (1, "5");
    testNumFives (0, "11");
    testNumFives (3, "5 5 5");
    testNumFives (0, "11 21 31 41");
    testNumFives (1, "5 11 21 31 41");
    testNumFives (1, "11 21 31 41 5");
    testNumFives (1, "11 21 5 31 41");
    testNumFives (5, "5 11 21 5 5 31 5 41 5");
    StdOut.println ("Finished tests");
  }
  public static void main1 (String[] args) {
    Trace.drawStepsOfMethod ("numFives");
    Trace.drawStepsOfMethod ("numFivesH");
    Trace.run ();
    Playground list0 = Playground.of ("5");
    Playground list1 = Playground.of ("5 11 5 5");
    int result = list1.numFives ();
    StdOut.println ("result: " + result);
  }
}

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