这个if语句梯子无法计算出折扣

这是我制作的一个程序，除不显示折扣价和最终成本外，其他所有功能均正常。我正在使用if else梯形图和扫描仪（这行是不必要的，但是如果我写的文字不够多，堆栈溢出将不会让我发问）如果您能帮助我，我将非常感谢。这是代码：

/**A Shopkeeper has decided to give out discount and an assured gifts to his customer on the basis of total cost of the item purchased:
TOTAL COST   DISCOUNT GIFT
<= 2000       5%      WALL CLOCK
2001 – 5000   10%     BAG
5001 – 10000   15%    ELECTRIC IRON
>10000         20%    WRIST WATCH
Write a program to input the total cost. Compute discount. Display the total cost, discount obtained,
final amount to be paid and the gift received by the customer.*/
import java.util.*;
class P1
{
    public static void main(String a[])
    {
        Scanner in = new Scanner(System.in);
        System.out.println("Input the total cost of the product...");
        double cost = in.nextDouble();
        if(cost<=0)
        {
            System.out.println("Invalid Price");
        }
        else if(cost<=2000)
        {
            System.out.println("Total cost of the product "+cost);
            System.out.println("Discount is 5%");
            double dis = 5/100*cost;
            double finalcost = dis+cost;
            System.out.println("Discounted price is "+dis);
            System.out.println("Final amount to be paid is "+finalcost);
            System.out.println("Gift recieved is a Wall Clock");
        }
        else if(cost>=2001 && cost<=5000)
        {
            System.out.println("Total cost of the product "+cost);
            System.out.println("Discount is 10%");
            double dis = 10/100*cost;
            double finalcost = dis+cost;
            System.out.println("Discounted price is "+dis);
            System.out.println("Final amount to be paid is "+finalcost);
            System.out.println("Gift recieved is a Bag");
        }
        else if(cost>=5001 && cost<=10000)
        {
            System.out.println("Total cost of the product "+cost);
            System.out.println("Discount is 15%");
            double dis = 15/100*cost;
            double finalcost = dis+cost;
            System.out.println("Discounted price is "+dis);
            System.out.println("Final amount to be paid is "+finalcost);
            System.out.println("Gift recieved is an Electric Iron");
        }
        else if(cost>10000)
        {
            System.out.println("Total cost of the product "+cost);
            System.out.println("Discount is 20%");
            double dis = 20/100*cost;
            double finalcost = dis+cost;
            System.out.println("Discounted price is "+dis);
            System.out.println("Final amount to be paid is "+finalcost);
            System.out.println("Gift recieved is a Wrist Watch");
        }
        else
        {
            System.out.println("Invalid Price");
        }
    }
}