need help with code

[indianj]

hello i wrote Statistician class. i am getting error:

A:\Statistician.java:19: cannot find symbol
symbol : class Random
location: class Statistician
Random r = new Random();
^
A:\Statistician.java:19: cannot find symbol
symbol : class Random
location: class Statistician
Random r = new Random();
^
2 errors

Process completed.

can some please tell me how to fix this error

here is my class:
import java.lang.*;
//import java.text.*;

public class Statistician
{

public static void main(String[] args)
{
Statistician s1 = new Statistician();
Statistician s2 = new Statistician();
Random r = new Random();
for (int i = 0; i < 5; i++)
{
s1.next(r.nextDouble()*100);
s2.next(r.nextDouble()*100);
}
Statistician newstat = Statistician.union(s1, s2);
System.out.println(s1);
System.out.println(s2);
System.out.println(newstat);

}


/**
* Initialize a new Statistician.
* @param - none
* <dt><b>Postcondition:</b><dd>
* This Statistician is newly initialized and has not yet been given any
* numbers.
**/

private int NumCount;
private double sum;
private double max;
private double min;

public Statistician()
{
NumCount = 0;
}

/**
* Add the numbers of another Statistician to this Statistician.
* @param <CODE>addend</CODE>
* a Statistician whose numbers will be added to this Statistician
* <dt><b>Precondition:</b><dd>
* The parameter, <CODE>addend</CODE>, is not null.
* <dt><b>Postcondition:</b><dd>
* The numbers from <CODE>addend</CODE> have been added to this
* Statistician. After the operation, this Statistician acts as if
* if was given all of its numbers and also given all of the numbers
* from the addend.
* @exception NullPointerException
* Indicates that <CODE>addend</CODE> is null.
**/

public void addAll(Statistician addend)
{
if (addend.NumCount != 0)
{
if (NumCount == 0)
{
NumCount = addend.NumCount;
sum = addend.sum;
max = addend.max;
min = addend.min;

}
else
{
NumCount += addend.NumCount;
sum += addend.sum;
//sum+=addend.NumCount;
if (addend.max > max)
max = addend.max;
if (addend.min < min)
min = addend.min;
}
}

}

/**
* Clear this Statistician.
* @param - none
* <dt><b>Postcondition:</b><dd>
* This Statistician is reinitialized as if it has never been given any
* numbers.
**/

public void clear()
{
NumCount = 0;
}

/**
* Compare this <CODE>Statistician</CODE> to another object for equality.
* @param <CODE>obj</CODE>
* an object with which this <CODE>Statistician</CODE> will be compared
* @return
* A return value of <CODE>true</CODE> indicates that
* <CODE>obj</CODE> refers to a
* <CODE>Statistican</CODE> object with the same length, sum, mean,
* minimum and maximum as this
* <CODE>Statistician</CODE>. Otherwise the return value is
* <CODE>false</CODE>.
* <dt><b>Note:</b><dt>
* If <CODE>obj</CODE> is null or does not refer to a
* <CODE>Statistician</CODE> object, then the answer is
* <CODE>false</CODE>.
**/
public boolean equals(Object obj)
{
if (obj instanceof Statistician)
{
Statistician stat = (Statistician) obj;
return (stat.NumCount == NumCount && stat.sum == sum &&
stat.max == max && stat.min == min);
}
return false;
}

/**
* Determine how many numbers have been given to this Statistician.
* @param - none
* @return
* the count of how many numbers have been given to this Statistician
* since it was initialized or reinitialized.
* <dt><b>Note:</b><dd>
* Giving a Statistician more than
* <CODE>Integer.MAX_VALUE</CODE> numbers, will
* cause failure with an arithmetic overflow.
**/

public int length()
{
return NumCount;
}

/**
* Determine the largest number that has been given
* to this Statistician.
* @param - none
* @return
* the largest number that has been given to this
* Statistician
* since it was initialized or reinitialized.
* <dt><b>Note:</b><dd>
* If <CODE>length()</CODE> is zero, then the answer from this method
* is <CODE>Double.NaN</CODE>.
**/

public double maximum()
{
if (NumCount == 0)
return Double.NaN;
return max;
//return maximum;
}

/**
* Determine the arithmetic average of all the numbers that have been given
* to this Statistician.
* @param - none
* @return
* the arithmetic mean of all the number that have been given to this
* Statistician
* since it was initialized or reinitialized.
* <dt><b>Note:</b><dd>
* If this Statistician has been given more than
* <CODE>Integer.MAX_VALUE</CODE> numbers, then this method fails
* because of arithmetic overflow.
* If <CODE>length()</CODE> is zero, then the answer from this method
* is <CODE>Double.NaN</CODE>.
* If <CODE>sum()</CODE> exceeds the bounds of double numbers, then the
* answer from this method may be
* <CODE>Double.POSITIVE_INFINITY</CODE> or
* <CODE>Double.NEGATIVE_INFINITY</CODE>.
**/

public double mean()
{
if (NumCount == 0)
return Double.NaN;
return sum / NumCount;
}


/**
* Determine the smallest number that has been given
* to this Statistician.
* @param - none
* @return
* the smallest number that has been given to this
* Statistician
* since it was initialized or reinitialized.
* <dt><b>Note:</b><dd>
* If <CODE>length()</CODE> is zero, then the answer from this method
* is <CODE>Double.NaN</CODE>.
**/
public double minimum()
{
if (NumCount == 0)
return Double.NaN;
return min;
}

/**
* Give a new number to this Statistician.
* @param <CODE>number</CODE>
* the new number that is being given the this Statistician
* <dt><b>Postcondition:</b><dd>
* The specified number has been given to this Statistician and
* it will be included in any subsequent statistics.
**/

public void next(double number)
{
if (NumCount == 0)
{
sum = number;
max = number;
//min = number;
}
else
{
sum += number;
if (number > max)
max = number;
if (number < min)
min = number;
}
NumCount++;
}

/**
* Determine the sum of all the numbers that have been given to this
* Statistician.
* @param - none
* @return
* the sum of all the number that have been given to this
* Statistician
* since it was initialized or reinitialized.
* <dt><b>Note:</b><dd>
* If the sum exceeds the bounds of double numbers, then the answer
* from this method may be
* <CODE>Double.POSITIVE_INFINITY</CODE> or
* <CODE>Double.NEGATIVE_INFINITY</CODE>.
**/
public double sum()
{
if (NumCount == 0)
return 0;
return sum;
}

/**
* Create a new Statistician that behaves as if it was given all the
* numbers from two other bags.
* @param <CODE>s1</CODE>
* the first of two Statisticians
* @param <CODE>s2</CODE>
* the second of two Statisticians
* <dt><b>Precondition:</b><dd>
* Neither s1 nor s2 is null.
* @return
* a new Statistician that acts as if it was given all the numbers from
* s1 and s2.
* @exception NullPointerException.
* Indicates that one of the arguments is null.
**/

public static Statistician union(Statistician s1, Statistician s2)
{
if (s1 == null || s2 == null)
throw new RuntimeException("..:: null pointer exception ::..");

Statistician result = new Statistician();
result.addAll(s1);
result.addAll(s2);
return result;
}
}

[CornedBee]

1) Use [code][/code] tags when posting here!

2) Remove the import java.lang.* line. It's implicit.

3) Add a line containing "import java.util.Random;". Random isn't part of the core library.

[ComputerJy]

this is your code, working:

import java.util.*;

public class Statistician {
  public static void main(String[] args) {
    Statistician s1 = new Statistician();
    Statistician s2 = new Statistician();
    Random r = new Random();
    for (int i = 0; i < 5; i++) {
      s1.next(r.nextDouble() * 100);
      s2.next(r.nextDouble() * 100);
    }
    Statistician newstat = Statistician.union(s1, s2);
    System.out.println(s1);
    System.out.println(s2);
    System.out.println(newstat);
  }

  /**
   * Initialize a new Statistician.
   * @param - none
   * <dt><b>Postcondition:</b><dd>
   * This Statistician is newly initialized and has not yet been given any
   * numbers.
   **/
  private int NumCount;
  private double sum;
  private double max;
  private double min;
  public Statistician() {
    NumCount = 0;
  }

  /**
   * Add the numbers of another Statistician to this Statistician.
   * @param <CODE>addend</CODE>
   * a Statistician whose numbers will be added to this Statistician
   * <dt><b>Precondition:</b><dd>
   * The parameter, <CODE>addend</CODE>, is not null.
   * <dt><b>Postcondition:</b><dd>
   * The numbers from <CODE>addend</CODE> have been added to this
   * Statistician. After the operation, this Statistician acts as if
   * if was given all of its numbers and also given all of the numbers
   * from the addend.
   * @exception NullPointerException
   * Indicates that <CODE>addend</CODE> is null.
   **/
  public void addAll(Statistician addend) {
    if (addend.NumCount != 0) {
      if (NumCount == 0) {
        NumCount = addend.NumCount;
        sum = addend.sum;
        max = addend.max;
        min = addend.min;
      }
      else {
        NumCount += addend.NumCount;
        sum += addend.sum;
        //sum+=addend.NumCount;
        if (addend.max > max) {
          max = addend.max;
        }
        if (addend.min < min) {
          min = addend.min;
        }
      }
    }
  }

  /**
   * Clear this Statistician.
   * @param - none
   * <dt><b>Postcondition:</b><dd>
   * This Statistician is reinitialized as if it has never been given any
   * numbers.
   **/
  public void clear() {
    NumCount = 0;
  }

  /**
   * Compare this <CODE>Statistician</CODE> to another object for equality.
   * @param <CODE>obj</CODE>
   * an object with which this <CODE>Statistician</CODE> will be compared
   * @return
   * A return value of <CODE>true</CODE> indicates that
   * <CODE>obj</CODE> refers to a
   * <CODE>Statistican</CODE> object with the same length, sum, mean,
   * minimum and maximum as this
   * <CODE>Statistician</CODE>. Otherwise the return value is
   * <CODE>false</CODE>.
   * <dt><b>Note:</b><dt>
   * If <CODE>obj</CODE> is null or does not refer to a
   * <CODE>Statistician</CODE> object, then the answer is
   * <CODE>false</CODE>.
   **/
  public boolean equals(Object obj) {
    if (obj instanceof Statistician) {
      Statistician stat = (Statistician) obj;
      return (stat.NumCount == NumCount && stat.sum == sum &&
              stat.max == max && stat.min == min);
    }
    return false;
  }

  /**
   * Determine how many numbers have been given to this Statistician.
   * @param - none
   * @return
   * the count of how many numbers have been given to this Statistician
   * since it was initialized or reinitialized.
   * <dt><b>Note:</b><dd>
   * Giving a Statistician more than
   * <CODE>Integer.MAX_VALUE</CODE> numbers, will
   * cause failure with an arithmetic overflow.
   **/
  public int length() {
    return NumCount;
  }

  /**
   * Determine the largest number that has been given
   * to this Statistician.
   * @param - none
   * @return
   * the largest number that has been given to this
   * Statistician
   * since it was initialized or reinitialized.
   * <dt><b>Note:</b><dd>
   * If <CODE>length()</CODE> is zero, then the answer from this method
   * is <CODE>Double.NaN</CODE>.
   **/
  public double maximum() {
    if (NumCount == 0) {
      return Double.NaN;
    }
    return max;
  }

  /**
   * Determine the arithmetic average of all the numbers that have been given
   * to this Statistician.
   * @param - none
   * @return
   * the arithmetic mean of all the number that have been given to this
   * Statistician
   * since it was initialized or reinitialized.
   * <dt><b>Note:</b><dd>
   * If this Statistician has been given more than
   * <CODE>Integer.MAX_VALUE</CODE> numbers, then this method fails
   * because of arithmetic overflow.
   * If <CODE>length()</CODE> is zero, then the answer from this method
   * is <CODE>Double.NaN</CODE>.
   * If <CODE>sum()</CODE> exceeds the bounds of double numbers, then the
   * answer from this method may be
   * <CODE>Double.POSITIVE_INFINITY</CODE> or
   * <CODE>Double.NEGATIVE_INFINITY</CODE>.
   **/
  public double mean() {
    if (NumCount == 0) {
      return Double.NaN;
    }
    return sum / NumCount;
  }

  /**
   * Determine the smallest number that has been given
   * to this Statistician.
   * @param - none
   * @return
   * the smallest number that has been given to this
   * Statistician
   * since it was initialized or reinitialized.
   * <dt><b>Note:</b><dd>
   * If <CODE>length()</CODE> is zero, then the answer from this method
   * is <CODE>Double.NaN</CODE>.
   **/
  public double minimum() {
    if (NumCount == 0) {
      return Double.NaN;
    }
    return min;
  }

  /**
   * Give a new number to this Statistician.
   * @param <CODE>number</CODE>
   * the new number that is being given the this Statistician
   * <dt><b>Postcondition:</b><dd>
   * The specified number has been given to this Statistician and
   * it will be included in any subsequent statistics.
   **/
  public void next(double number) {
    if (NumCount == 0) {
      sum = number;
      max = number;
    }
    else {
      sum += number;
      if (number > max) {
        max = number;
      }
      if (number < min) {
        min = number;
      }
    }
    NumCount++;
  }

  /**
   * Determine the sum of all the numbers that have been given to this
   * Statistician.
   * @param - none
   * @return
   * the sum of all the number that have been given to this
   * Statistician
   * since it was initialized or reinitialized.
   * <dt><b>Note:</b><dd>
   * If the sum exceeds the bounds of double numbers, then the answer
   * from this method may be
   * <CODE>Double.POSITIVE_INFINITY</CODE> or
   * <CODE>Double.NEGATIVE_INFINITY</CODE>.
   **/
  public double sum() {
    if (NumCount == 0) {
      return 0;
    }
    return sum;
  }

  /**
   * Create a new Statistician that behaves as if it was given all the
   * numbers from two other bags.
   * @param <CODE>s1</CODE>
   * the first of two Statisticians
   * @param <CODE>s2</CODE>
   * the second of two Statisticians
   * <dt><b>Precondition:</b><dd>
   * Neither s1 nor s2 is null.
   * @return
   * a new Statistician that acts as if it was given all the numbers from
   * s1 and s2.
   * @exception NullPointerException.
   * Indicates that one of the arguments is null.
   **/
  public static Statistician union(Statistician s1, Statistician s2) {
    if (s1 == null || s2 == null) {
      throw new RuntimeException("..:: null pointer exception ::..");
    }
    Statistician result = new Statistician();
    result.addAll(s1);
    result.addAll(s2);
    return result;
  }
}