如何解决第二种方法的“非法开始表达”错误？

Question

我正在尝试使用嵌套的 if/else 结构和 while 循环来完成分配。 但是，不知何故，我的第二种方法会导致错误。 如果你能帮助我，请告诉我，因为这是我关于 SO 的第一个问题。

我试过用括号关闭第一种方法，但这只会导致更多错误。 我不知道从这里到 go 的其他地方，我已经在谷歌上寻找帮助。

import java.util.*;
public class PA1 {


  public static void main(String[] args) {
    Scanner in = new Scanner(System.in);

    while((senitel == 'y')||(senitel == 'Y')); {
      menu();
      System.out.printf("Enter your choice: ");
      choice = in.nextInt();
      redo = in.nextLine();
      while(choose ==true) {
        if(choice==1) {
          choice = false;
          computer = "HP Envy 13\n";
          System.out.printf("Enter the quantity for the %s", computer);
          quantity = in.nextInt();
          subtotal = subtotal +799.99; }
        else if (choice==2) {
          choose = false;
          computer = "Asus ZenBook 13 UX333FA\n";
          System.out.printf("Enter qunatity for the %s", computer);
          quantity = in.nextInt();
          subtotal = subtotal + 849.99; }
        else {
          choose = false;
          System.out.println("In Else");
          System.out.printf("Invalid choice! Try again.\n");
          System.out.printf("Enter 'Y' to add a laptop to your purchase or 'N' to exit: ");
          redo = in.nextLine(); }

        if((choice>=1)&&(choice<=5)) {
          choice = true;}
        else {
          choice = false;
          menu();
          choice = in.nextInt();}}

      redo = in.nextLine();
      System.out.printf("Enter 'Y' to add a laptop to your purchase or 'N' to exit: ");
      reply = in.nextLine();
      senitel = reply.charAt(0);}

    System.out.println("Out");
    choice = 3;

    if(choice>0) {
      if(choice<6) {
        System.out.printf("LAPTOP ORDER SUMMARY\n\n");
        System.out.printf("%s",orderSummary);
        System.out.printf("Date:\n");
        System.out.printf("Time:\n\n");
        tax = subtotal + .0825;
        total = subtotal + tax;
        int trigger =1;

     String laptop = "";
     int lineItem = 0;
     if(trigger == 1) {
       orderSummary += String.format("%n%,-9d %-30s %8s $%,17.2f",
                         qty, laptop, " ", lineItem);
       trigger = 0; }
     else {
       orderSummary += String.format("%n%,-9d %-30s %9s %,17.2f",
                         qty, laptop, " ", lineItem);}


     orderSummary += String.format("%n%n%34s Subtotal %6s %,17.2f"
                                     + "%n%31s Tax @ 8.25%% %6s %,17.2f"                    
                                     + "%n%n%37s TOTAL %5s $%,17.2f%n",
                                     " ", " ", subtotal,
                                     " ", " ", tax,
                                     " ", " ", total);
     System.out.printf("%s", orderSummary); }}



public static void menu(){
Calendar dateTime = Calendar.getInstance();
System.out.printf("%nTOP LAPTOPS OF %tY"
                    + "%n%n1.  %-23s %7s $%,9.2f"
                    + "%n2.  %-23s %8s %,9.2f"
                    + "%n3.  %-23s %8s %,9.2f"
                    + "%n4.  %-23s %8s %,9.2f"
                    + "%n5.  %-23s %8s %,9.2f"
                    + "%n%nEnter your choice:  ",
                    dateTime,
                    "HP Envy 13", " ", 799.99,
                    "Asus ZenBook 13 UX333FA", " ", 849.99,
                    "Dell XPS 13", " ", 989.99,
                    "Alienware Area 51-m", " ", 1999.99,
                  "Razer Blade Stealth", " ", 1299.00); }



public static void trig() {
  int trigger = 1;
  String orderSummary = "";
  int quantity = 0;
  String laptop = "";
  int lineItem = 0;
  if(trigger==1) {
    orderSummary += String.format("%n%, -9d %-30s %8%s $%, 17.2f",
                                  quantity, laptop, " ", lineItem);
    trigger =0; }
  else {
    orderSummary += String.format("%n%, -9d %-30s %9s %, 17.2f",
                                  quantity, laptop, lineItem); }

  orderSummary += String.format("%n%n%34s Subtotal %6s %,17.2f"
                                     + "%n%31s Tax @ 8.25%% %6s %,17.2f"                    
                                     + "%n%n%37s TOTAL %5s $%,17.2f%n");

  System.out.printf("%s", orderSummary); }}

Answer 1

那么这里有一个问题：

while( (senitel == 'y') || (senitel == 'Y') );
{

看到最后那个分号了吗？ 可能不是你想要的。

使用 IDE 自动缩进您的代码。 然后 go 通过所有这些并修复语法错误。 严重地。

Answer 2

你忘记了大括号。

这是您的固定示例：

import java.util.*;
public class PA1 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);

        while ((senitel == 'y') || (senitel == 'Y')) ;
        {
            menu();
            System.out.printf("Enter your choice: ");
            choice = in.nextInt();
            redo = in.nextLine();
            while (choose == true) {
                if (choice == 1) {
                    choice = false;
                    computer = "HP Envy 13\n";
                    System.out.printf("Enter the quantity for the %s", computer);
                    quantity = in.nextInt();
                    subtotal = subtotal + 799.99;
                }
                else if (choice == 2) {
                    choose = false;
                    computer = "Asus ZenBook 13 UX333FA\n";
                    System.out.printf("Enter qunatity for the %s", computer);
                    quantity = in.nextInt();
                    subtotal = subtotal + 849.99;
                }
                else {
                    choose = false;
                    System.out.println("In Else");
                    System.out.printf("Invalid choice! Try again.\n");
                    System.out
                            .printf("Enter 'Y' to add a laptop to your purchase or 'N' to exit: ");
                    redo = in.nextLine();
                }

                if ((choice >= 1) && (choice <= 5)) {
                    choice = true;
                }
                else {
                    choice = false;
                    menu();
                    choice = in.nextInt();
                }
            }

            redo = in.nextLine();
            System.out.printf("Enter 'Y' to add a laptop to your purchase or 'N' to exit: ");
            reply = in.nextLine();
            senitel = reply.charAt(0);
        }

        System.out.println("Out");
        choice = 3;

        if (choice > 0) {
            if (choice < 6) {
                System.out.printf("LAPTOP ORDER SUMMARY\n\n");
                System.out.printf("%s", orderSummary);
                System.out.printf("Date:\n");
                System.out.printf("Time:\n\n");
                tax = subtotal + .0825;
                total = subtotal + tax;
                int trigger = 1;

                String laptop = "";
                int lineItem = 0;
                if (trigger == 1) {
                    orderSummary += String.format("%n%,-9d %-30s %8s $%,17.2f",
                                                  qty, laptop, " ", lineItem);
                    trigger = 0;
                }
                else {
                    orderSummary += String.format("%n%,-9d %-30s %9s %,17.2f",
                                                  qty, laptop, " ", lineItem);
                }


                orderSummary += String.format("%n%n%34s Subtotal %6s %,17.2f"
                                                      + "%n%31s Tax @ 8.25%% %6s %,17.2f"
                                                      + "%n%n%37s TOTAL %5s $%,17.2f%n",
                                              " ", " ", subtotal,
                                              " ", " ", tax,
                                              " ", " ", total);
                System.out.printf("%s", orderSummary);
            }
        }


    }

    public static void menu() {
        Calendar dateTime = Calendar.getInstance();
        System.out.printf("%nTOP LAPTOPS OF %tY"
                                  + "%n%n1.  %-23s %7s $%,9.2f"
                                  + "%n2.  %-23s %8s %,9.2f"
                                  + "%n3.  %-23s %8s %,9.2f"
                                  + "%n4.  %-23s %8s %,9.2f"
                                  + "%n5.  %-23s %8s %,9.2f"
                                  + "%n%nEnter your choice:  ",
                          dateTime,
                          "HP Envy 13", " ", 799.99,
                          "Asus ZenBook 13 UX333FA", " ", 849.99,
                          "Dell XPS 13", " ", 989.99,
                          "Alienware Area 51-m", " ", 1999.99,
                          "Razer Blade Stealth", " ", 1299.00);
    }


    public static void trig() {
        int trigger = 1;
        String orderSummary = "";
        int quantity = 0;
        String laptop = "";
        int lineItem = 0;
        if (trigger == 1) {
            orderSummary += String.format("%n%, -9d %-30s %8%s $%, 17.2f",
                                          quantity, laptop, " ", lineItem);
            trigger = 0;
        }
        else {
            orderSummary += String.format("%n%, -9d %-30s %9s %, 17.2f",
                                          quantity, laptop, lineItem);
        }

        orderSummary += String.format("%n%n%34s Subtotal %6s %,17.2f"
                                              + "%n%31s Tax @ 8.25%% %6s %,17.2f"
                                              + "%n%n%37s TOTAL %5s $%,17.2f%n");

        System.out.printf("%s", orderSummary);
    }
}

使用一些指向错误的 IDE。