总的来说，这个代码应该询问客户姓名、会员级别和原始购买价格。它应该将所有这些存储在它们各自的变量中，如果输入的不是接受的成员级别，则程序应该退出。将所有变量存储后，客户姓名、会员等级、原购买价格、促销价格、节省金额应以本文末尾的格式打印出来。另外，您能否告诉我我的变量是否正确命名以及整个代码的格式是否正确。提前感谢您的帮助！
import java.util.*;
public class Discount{
public static void main(String[] args){
Scanner keyboard = new Scanner(System.in);
double purchase = 0.0;
double platinum = (purchase * .2);
double gold = (purchase * .15);
double silver = (purchase * .1);
String Platinum = null;
String Gold = null;
String Silver = null;
String customerName = null;
String level = null;
double discount = 0.0;
System.out.print("Please enter a customer name: ");
customerName = keyboard.nextLine();
System.out.print("Please enter the customer's member level: ");
level = keyboard.nextLine();
如果打印了 Silver、Gold 或 Platinum 以外的任何内容，则该部分应该退出程序；但是，无论输入什么，它都会退出。如果我把这部分去掉，它会继续询问原始购买价格是多少，但不会打印任何结果。
if (level != "Platinum" || level != "Gold" || level != "Silver")
{
System.exit(0);
}
System.out.print("Please enter the origianl purchase price: ");
purchase = keyboard.nextDouble();
if (level.equals(Platinum) && purchase > 500)
{
discount = (platinum - (purchase*.05));
System.out.println("Congratualations, " + customerName + "!");
System.out.println("As a " + level + " level cardholder, you have received a 25% discount during Bedlam.");
System.out.printf("%.2f\n", "Origianl purchase price: $" + purchase);
System.out.printf("%.2f\n", "Promotional price: $" + discount);
System.out.printf("%.2f\n", "Amount saved: $" + (purchase-discount));
}
else if (level.equals(Platinum))
{
discount = (platinum);
System.out.println("Congratualations, " + customerName + "!");
System.out.println("As a " + level + " level cardholder, you have received a 20% discount during Bedlam.");
System.out.printf("%.2f\n", "Origianl purchase price: $" + purchase);
System.out.printf("%.2f\n", "Promotional price: $" + discount);
System.out.printf("%.2f\n", "Amount saved: $" + (purchase-discount));
}
else if (level.equals(Gold))
{
discount = (gold);
System.out.println("Congratualations, " + customerName + "!");
System.out.println("As a " + level + " level cardholder, you have received a 15% discount during Bedlam.");
System.out.printf("%.2f\n", "Origianl purchase price: $" + purchase);
System.out.printf("%.2f\n", "Promotional price: $" + discount);
System.out.printf("%.2f\n", "Amount saved: $" + (purchase-discount));
}
else if (level.equals(Silver))
{
discount = (silver);
System.out.println("Congratualations, " + customerName + "!");
System.out.println("As a " + level + " level cardholder, you have received a 10% discount during Bedlam.");
System.out.printf("%.2f\n", "Origianl purchase price: $" + purchase);
System.out.printf("%.2f\n", "Promotional price: $" + discount);
System.out.printf("%.2f\n", "Amount saved: $" + (purchase-discount));
}
/* Example:
Congratulations, Marge Simpson!
As a Silver level cardholder, you received a 10% discount during Bedlam.
Original purchase price: $500.20
Promotional price: $450.18
Amount saved: $50.02 */
}
}