我知道switch中的任何变量都必须在case语句的范围之外声明，但是我试图将所有计算都抛出Switch范围之外，但我仍然没有从这个脚本中获得我想要的“总计”结果。有人可以帮我吗？我只想在这个脚本的最后一段中使用最后一个块注释语句。
import java.util.Scanner;
public class script
{
public static void main(String[] args)
{
//initialization
Scanner key = new Scanner(System.in);
final double COST_WINE = 13.99; // What is the size of the bottle of wine? ***********************************
final double COST_BEER_6 = 11.99, COST_BEER_12 = 19.99, COST_BEER_24 = 34.99;
final double spirits_750 = 25.99, spirits_1000 = 32.99;
final double gst = 0.05; //confirm if this number is right***************************************************
final double deposit750 = 0.10, deposit1000 = 0.25;
double wineSubTotal, wineTotal , total_cost;
double beer_6_SubTotal, beer_6_Total;
double beer_12_SubTotal, beer_12_Total;
double beer_24_SubTotal, beer_24_Total;
double spirits_750_SubTotal, spirits_750_Total;
double spirits_1000_SubTotal, spirits_1000_Total;
int wineQuantity, beer_6_Quantity, beer_12_Quantity;
int beer_24_Quantity, spirits_750_Quantity, spirits_1000_Quantity;
int beer_choice, spirits_choice;
char choice;
String input, again;
//loop for fun
for(int i = 0 ; i < 40; i++)
{
System.out.print("-");
}
System.out.printf("\n*** Welcome to Yoshi's Liquor Mart ***\n");
System.out.printf("Today's date is \n"); // Reserved for date***********************************************
//another loop for fun
for(int i = 0 ; i < 40; i++)
{
System.out.print("-");
}
//first actual loop, not for fun anymore
do
{
System.out.printf("\nWine is $13.99" + "\nBeer 6 pack is $11.99\n" + "Beer 12 pack is $19.99\n" +
"Beer 24 pack is $34.99\n" + "Spirits 750 mL is $25.99\n" + "Spirits 1000 mL is $32.99\n" +
"What is the item being purchased?\n" + "W for Wine, B for Beer and S for Spirits, or X to quit: ");
input = key.nextLine();
choice = input.charAt(0);
switch(choice)
{
case('w'):
case('W'):
System.out.printf("\nHow many bottles of wine is being purchased? ");
wineQuantity = key.nextInt();
wineSubTotal = wineQuantity * COST_WINE;
wineTotal = (wineSubTotal * gst) + wineSubTotal + (deposit750 * wineQuantity);
System.out.printf("\nThe cost of " + wineQuantity +
" bottles of wine including GST and deposit is %.2f\n", wineTotal);
break;
case('b'):
case('B'):
System.out.printf("What is size of the beer pack?\n" + "6, 12 or 24?");
beer_choice = key.nextInt();
if(beer_choice == 6)
{
System.out.printf("\nHow many 6 pack of beer is being purchased?");
beer_6_Quantity = key.nextInt();
beer_6_SubTotal = beer_6_Quantity * COST_BEER_6;
beer_6_Total = (beer_6_SubTotal * gst) + beer_6_SubTotal;
System.out.printf("\nThe cost of %d cases of 6 pack of beer" +
"including GST and deposit is %.2f\n", beer_6_Quantity, beer_6_Total);
}
else if(beer_choice == 12)
{
System.out.printf("How many 12 pack of beer is being purchased?");
beer_12_Quantity = key.nextInt();
beer_12_SubTotal = beer_12_Quantity * COST_BEER_12;
beer_12_Total = (beer_12_SubTotal * gst) + beer_12_SubTotal;
System.out.printf("\nThe cost of %d cases of 12 pack of beer" +
"including GST and deposit is %.2f\n", beer_12_Quantity, beer_12_Total);
}
else if(beer_choice == 24)
{
System.out.printf("How many 24 pack of beer is being purchased?");
beer_24_Quantity = key.nextInt();
beer_24_SubTotal = beer_24_Quantity * COST_BEER_24;
beer_24_Total = (beer_24_SubTotal * gst) + beer_24_SubTotal;
System.out.printf("\nThe cost of %d cases of 24 pack of beer" +
"including GST and deposit is %.2f\n", beer_24_Quantity, beer_24_Total);
}
else
{
System.out.println("Invalid number");
}
break;
case('s'):
case('S'):
System.out.printf("What is size of Spirits?\n" + "750ml or 1000ml?");
spirits_choice = key.nextInt();
if(spirits_choice == 750)
{
System.out.printf("How many bottles are being purchased?");
spirits_750_Quantity = key.nextInt();
spirits_750_SubTotal = spirits_750_Quantity * spirits_750;
spirits_750_Total = (spirits_750_SubTotal * gst) + spirits_750_SubTotal +
(deposit750 * spirits_750_Quantity);
System.out.printf("\nThe cost of %d bottle(s) of Spirits 750ml " +
"including GST and deposit is %.2f\n", spirits_750_Quantity, spirits_750_Total);
}
else if(spirits_choice == 1000)
{
System.out.printf("How many bottles are being purchased?");
spirits_1000_Quantity = key.nextInt();
spirits_1000_SubTotal = spirits_1000_Quantity * spirits_1000;
spirits_1000_Total = (spirits_1000_SubTotal * gst) + spirits_1000_SubTotal +
(deposit1000 * spirits_1000_Quantity);
System.out.printf("\nThe cost of %d bottle(s) of Spirits 1000ml " +
"including GST and deposit is %.2f\n", spirits_1000_Quantity, spirits_1000_Total);
}
else
{
System.out.println("Invalid number");
}
break;
case('x'):
case('X'):
break;
default:
System.out.printf("Invalid choice");
break;
}
System.out.println("Is this customer's order complete? ");
again = key.nextLine();
}
while(again.equals("n"));
//Total cost
/*total_cost = wineTotal + beer_6_Total + beer_12_Total + beer_24_Total +
spirits_750_Total + spirits_1000_Total;
System.out.printf("The total cost for this customer is %f", total_cost);*/
key.close(); //There was a warning message(not error), so I found out on StackOverFlow that this would close the Scanner
}
}
答案 0 :(得分：0)
如果你想在循环之后使用wineTotal（正如你的注释掉的代码似乎暗示的那样），你应该在声明中将它初始化为0，这样它也有一个值，如果没有正在购买葡萄酒。
如果您希望在case语句的每个switch中声明局部变量（就像我经常这样），请将它们放在{和}中：
case ('w'):
case ('W'): {
System.out.printf("\nHow many bottles of wine is being purchased? ");
int wineQuantity = key.nextInt();
double wineSubTotal = wineQuantity * COST_WINE;
wineTotal = (wineSubTotal * gst) + wineSubTotal + (deposit750 * wineQuantity);
System.out.printf(
"\nThe cost of " + wineQuantity + " bottles of wine including GST and deposit is %.2f\n",
wineTotal);
}
break;
你的程序第一次循环运行正常。即使我回复n到Is this customer's order complete?，程序也会终止。我认为这是因为在阅读了key.nextInt()的一些瓶子之后，程序仍然没有在数字后读取换行符。因此，当询问订单是否完整并使用key.nextLine()读取答案时，程序将使用数量的剩余部分，通常是空字符串，不等于"n"，因此它退出do循环。
对于你的下一个问题os Stack Overflow（如果你有一个），James K的建议仍然是一个很好的建议：在发布前制作一个最小，完整和可验证的例子。