一上来见到这些回复，谢谢大家了，不过还是有问题
以下是改过后仍然出错的程序，为什么，是不是因为数组类型的问题？

interface ComputeTotalSales
{
public double totalSalesByYear();
}
class Television implements ComputeTotalSales
{
double a;
Television(double a)
{
this.a=a;
a=155555.22;

}
public double totalSalesByYear()
{
System.out.println("电视机的年销售额：%f"+a);
return a;
}
}
class Computer implements ComputeTotalSales
{
double b;
Computer(double b)
{
this.b=b;
b=255555.22;

}
public double totalSalesByYear()
{
System.out.println("计算机的年销售额：%f"+b);
return b;
}
}
class Mobile implements ComputeTotalSales
{
double c;
Mobile(double c)
{
this.c=c;
c=355555.22;

}
public double totalSalesByYear()
{
System.out.println("移动电话的年销售额："+c);
return c;
}
}
class Shop
{

Shop()
{
ComputeTotalSales[] cts=new ComputeTotalSales[3];
cts[0]=new Television(double a);//需要 ".class" 需要 ';'
cts[1]=new Computer(double b);//需要 ".class" 需要 ';'
cts[2]=new Mobile(double c);//需要 ".class" 需要 ';'
}


double sales(double d)
{
double d=0;
int i;
for(i=0;i<3;i++)
{
d=d+cts[i].totalSalesByYear();
}
System.out.println("总年销售额：%f"+d);
return d;

}

}
public class Salesperyear
{
public static void main (String args[])
{
Shop shop=new Shop();
shop.sales(double d);//需要 ".class" 需要 ';'
}
}

[此贴子已经被作者于2007-10-18 16:42:21编辑过]

这个问题上面不是已经给你写了吗？