LastDigitDistribution.java
/**
This class analyzes the distribution of the last digit of values
from a sequence.
*/
public class LastDigitDistribution
{
private int[] counters;
/**
Constructs a distribution whose counters are set to zero.
*/
public LastDigitDistribution()
{
counters = new int[10];
}
/**
Processes values from this sequence.
@param seq the sequence from which to obtain the values
@param valuesToProcess the number of values to process
*/
public void process(Sequence seq, int valuesToProcess)
{
for (int i = 1; i <= valuesToProcess; i++)
{
int value = seq.next();
int lastDigit = value % 10;
counters[lastDigit]++;
}
}
/**
Displays the counter values of this distribution.
*/
public void display()
{
// calculate scale factor
...
for (int i = 0; i < counters.length; i++)
{
// System.out.println(i + ": " + counters[i]);
...
}
}
}
Use the following files:
RandomSequence.java
public class RandomSequence implements Sequence
{
public int next()
{
return (int) (Integer.MAX_VALUE * Math.random());
}
}
Sequence.java
public interface Sequence
{
int next();
}
SequenceDemo.java
public class SequenceDemo
{
public static void main(String[] args)
{
LastDigitDistribution dist1 = new LastDigitDistribution();
dist1.process(new SquareSequence(), 1000);
dist1.display();
System.out.println();
LastDigitDistribution dist2 = new LastDigitDistribution();
dist2.process(new RandomSequence(), 1000);
dist2.display();
}
}
SquareSequence.java
public class SquareSequence implements Sequence
{
private int n;
public int next()
{
n++;
return n * n;
}
}