改一下,去掉内部类Test
编译javac Averager.java
运行java Averagerpublic class Averager
{
private int n = 0;
private double sum = 0.0,sumOfSquares = 0.0;
public void addDatum(double x)
{
n++;
sum += x;
sumOfSquares += x * x;
}
public double getAverage()
{
return sum/n;
}
public double getStandardDeviation()
{
return Math.sqrt(((sumOfSquares - sum*sum/n)/n));
}
public double getNum() { return n ;}
public double getSum() { return sum; }
public double getSumOfSquares() { return sumOfSquares; }
public void reset() { n = 0; sum =0.0; sumOfSquares = 0.0;}
//public static class Test
//{
public static void main(String args[])
{
Averager a = new Averager();
for(int i = 1; i <= 100; i++) a.addDatum(i);
System.out.println("Averager: " + a.getAverage());
System.out.println("Standard Deviation: " + a.getStandardDeviation());
System.out.println("N: " + a.getNum());
System.out.println("Sum: " + a.getSum());
System.out.println("Sum of squares: " + a.getSumOfSquares());
}
//}
}
编译javac Averager.java
运行java Averagerpublic class Averager
{
private int n = 0;
private double sum = 0.0,sumOfSquares = 0.0;
public void addDatum(double x)
{
n++;
sum += x;
sumOfSquares += x * x;
}
public double getAverage()
{
return sum/n;
}
public double getStandardDeviation()
{
return Math.sqrt(((sumOfSquares - sum*sum/n)/n));
}
public double getNum() { return n ;}
public double getSum() { return sum; }
public double getSumOfSquares() { return sumOfSquares; }
public void reset() { n = 0; sum =0.0; sumOfSquares = 0.0;}
//public static class Test
//{
public static void main(String args[])
{
Averager a = new Averager();
for(int i = 1; i <= 100; i++) a.addDatum(i);
System.out.println("Averager: " + a.getAverage());
System.out.println("Standard Deviation: " + a.getStandardDeviation());
System.out.println("N: " + a.getNum());
System.out.println("Sum: " + a.getSum());
System.out.println("Sum of squares: " + a.getSumOfSquares());
}
//}
}
{
private int n = 0;
private double sum = 0.0,sumOfSquares = 0.0;
public void addDatum(double x)
{
n++;
sum += x;
sumOfSquares += x * x;
}
public double getAverage()
{
return sum/n;
}
public double getStandardDeviation()
{
return Math.sqrt(((sumOfSquares - sum*sum/n)/n));
}
public double getNum() { return n ;}
public double getSum() { return sum; }
public double getSumOfSquares() { return sumOfSquares; }
public void reset() { n = 0; sum =0.0; sumOfSquares = 0.0;}
}
public class Test
{
public static void main(String args[])
{
Averager a = new Averager();
for(int i = 1; i <= 100; i++) a.addDatum(i);
System.out.println("Averager: " + a.getAverage());
System.out.println("Standard Deviation: " + a.getStandardDeviation());
System.out.println("N: " + a.getNum());
System.out.println("Sum: " + a.getSum());
System.out.println("Sum of squares: " + a.getSumOfSquares());
}
}
把Averager放在Test类里