recursion

[kdeighan]

I have to complete the program below which is intended to print
the value of the largest element in an array of doubles. This is what I have so far w/ the test class but i'm stuck with tester method (2 parameters) & tester method(1parameter)

/*
* A class to test the ArrayTools class
*/
public class ArrayToolsTest
{
public static void main(String[] args)
{
double[] myArray = { ... }; // Fill this array with any doubles
ArrayTools tester = new ArrayTools(myArray);
System.out.println("The largest value in the array is " + tester.findLargest());
}
}

/*
* This class contains methods which would be helpful to use with an array.
*/
public class ArrayTools
{
public ArrayTools(double[] myArray)
{
doubs = myArray;
}

public boolean tester()
{
}


private boolean tester(//PARAMETERS?)
{
}

double[] doubs = new double[100];
double maximum;
}

[CaptainMorgan]

You titled the thread "recursion", but didn't say whether you wanted to use it and I do not see your attempt at it. You also call a method findLargest, so I don't understand why you need the tester methods. The following compiles and runs - but I'm leaving the findLargest logic up to you - if you get stuck post how you've attempted it. Please use code tags.

Code:

public class ArrayTools {
  double[] doubs = new double[100];
  double maximum;     
  
  public ArrayTools(double[] myArray) {
    this.doubs = myArray;
  }

  public boolean tester() {
    return true;
  }
  
  private boolean tester(double i, int j) {
    return true;
  }

  public double findLargest() {
    // for all values k in doubs, 
    //  iterate over doubs[k], 
    //  compare next value to values already compared
    return maximum;
  }
}

Code:

public class ArrayToolsTest{
  public static void main(String[] args) {
    double[] myArray = { 1.2, 5.7, 4.3, 17.24, 12.34 }; // Fill this array with any doubles
    ArrayTools tester = new ArrayTools(myArray);
    System.out.println("The largest value in the array is " + tester.findLargest());
  }
}

[kdeighan]

okay i got the base case down, but i don't think i called the recursive method correctly at all.

Code:

  public double findLargest(myArray)
  {
        
        if( k == 0)
        {
            maximum = doubs[k];
            return maximum;
        }
        else return (myArray.findLargest(k-1)
   }

[portis2003]

you don't need to use recursion to find the largest double in an array of doubles. try adding this method in.

Code:

public double findLargest(double[] myArray)     //so this method is taking your array   
{                                                   //as a parameter
int maximum = myArray[0];
for(int i = 0; i < myArray.length; i++)
{
     if(myArray[i] > maximum)
          {
               maximum = myArray[i];
          }
}
return maximum;
}