Question

I’m am trying to determine how many comparisons are made for both the linear and binary searching techniques. can someone tell me how to print out the number of times a loop happened in each case? for example, to find 5 in the first array the loop happens only one time.

       public static void main(String[] args) {
    // TODO code application logic here
    int[] values  = {5, 8, 6, 2, 1, 7, 9, 3, 0, 4, 20, 50, 11, 22, 32, 120};
    int[] valuesSorted  = {1, 2, 3, 4, 5, 8, 16, 32, 51, 57, 59, 83, 90, 104};
    DisplayArray(values);
    DisplayArray(valuesSorted);

    int index;
    index = IndexOf(1, values);
    System.out.println("1 is at values location " + index);
    index = IndexOf(120, values);

    System.out.println("120 is at values location " + index);

    index = BinaryIndexOf(104, valuesSorted);
    System.out.println("104 is at values Sorted location " + index);

    index = BinaryIndexOf(90, valuesSorted);
    System.out.println("90 is at values Sorted location " + index);       

}


public static int IndexOf(int value, int[] array)
{

    for (int i=0; i < array.length; i++)
    {

        if(array[i] == value)
            return i;

    }

    return -1;


}
public static int BinaryIndexOf(int value, int [] array)
{
    int start = 0;
    int end = array.length -1;
    int middle;

    while (end >= start)
    {
        middle = (start + end ) /2;
        if (array[middle]== value)
            return middle;
        if (array[middle]< value)
            start = middle + 1;
        else 
            end = middle - 1;
    }
    return -1;

}

public static void DisplayArray(int[] array)
{
    for (int a : array)
    {
        System.out.print(a + " ");
    }
    System.out.println();
}

}

Answer 1

For the linear search, you can do something like this:

public static int IndexOf(int value, int[] array)
{
    for (int i=0; i < array.length; i++)
    {

        if(array[i] == value)
        {            
            System.out.println("Linear search: Number of comparisons = " + (i + 1));
            return i;
        }
    }

    return -1;
}

For the Binary Search, do this:

public static int BinaryIndexOf(int value, int [] array)
{
    int start = 0;
    int end = array.length -1;
    int middle;
    int loopCount = 0;
    while (end >= start)
    {
        loopCount++;
        middle = (start + end ) /2;
        if (array[middle]== value)
        {
            System.out.println("Binary search: Number of times looped = " + loopCount); 
            return middle;
        }
        if (array[middle]< value)
            start = middle + 1;
        else 
            end = middle - 1;
    }
    System.out.println("Binary search: Number of times looped = " + loopCount);
    return -1;

}