public static void main(String[] args) {
Scanner input = new Scanner(System.in);
boolean start = true;
while(start)
System.out.printf("%70s %n", " @@@@@ Zoos Australia @@@@@ " + "\n");
System.out.printf("%57s %n", "Main Menu" + "\n");
System.out.printf("%72s %n", "Zoo has the following ticketing options:");
System.out.print("\n");
System.out.printf("%59s %n", "1 = Child (4-5 yrs)");
System.out.printf("%59s %n", "2 = Adult (18+ yrs)");
System.out.printf("%60s %n", "3 = Senior (60+ yrs)");
System.out.println("\n");
String choose1 = "";
String choose2 = "";
String choose3 = "";
String selected = "";
int option = 0;
{
System.out.print("Please select an option: ");
option = input.nextInt();
if (option == 1) {
choose1 = "Child";
selected = choose1;
} else if (option == 2) {
choose2 = "Adult";
selected = choose2;
} else if (option == 3) {
choose3 = "Senior";
selected = choose3;
}
}
// done
System.out.println("\n");
int price = 0;
int tickets = 0;
System.out.print("Enter the number of tickets: ");
tickets = input.nextInt();
if (selected == choose1) {
price = 10;
} else if (selected == choose2) {
price = 20;
} else if (selected == choose3) {
price = 15;
}
System.out.println("\n");
System.out.print("You are purchasing " + tickets + " " + selected + " tickets at " + "$" + price + " each!");
System.out.println("\n");
int confirm = 0;
System.out.print("Press 1 to confirm purchase: ");
confirm = input.nextInt();
if (confirm != 1) {
System.out.print("Incorrect Key. Please return to Main Menu");
System.out.println("\n");
} else {
break;
}
System.out.println("\n");
int total = tickets;
price = total * price;
System.out.print("Total amount for " + selected + " tickets: " + "$" + price);
System.out.println("\n");
String pick = "";
System.out.print("Do you wish to continue: ");
input.next();
System.out.println("\n");
if (pick == "no") {
System.out.print("Total amount payable is: " + "$" + price);
System.out.println("\n");
System.out.print("Have a nice day!");
System.out.println("\n");
}}}
尝试在程序末尾执行此操作，要求用户使用某种方法或其他方法使它“无法继续”，但是无法使其正常工作。程序仅返回主菜单，或者程序结束并显示总消息“应付总额...”等。我尝试将其与continue和break一起使用。将布尔值与true和false一起使用。但是没有运气。谢谢任何可能为我解决此问题的人。
首先，您必须将用户输入分配给变量：pick = input.next()。之后，问题是您使用==运算符将用户的输入字符串与“否”字符串进行比较。比较引用类型（对象）（而String是对象）时，在大多数情况下，==运算符会给您带来不可预测的结果，因为它比较引用（对象在内存中的地址）而不是实际内容。请记住，您始终必须使用.equals()方法。当用户输入为“ no”时，还必须中断循环。
关于此问题的材料很多。例如，您可以检查此How do I compare strings in Java?
P.S。我迅速查看了其余代码，并添加了一些其他注释，这可能有助于您进行改进。学习Java祝您好运！
Scanner input = new Scanner(System.in);
// boolean start = true; you don't need this line
while(true) { // 'true' condition makes it an infinite loop until you use break
// You also have to surround your while loop with curly braces,
// otherwise you fall into an infinite loop
System.out.printf("%70s %n", " @@@@@ Zoos Australia @@@@@ \n");
System.out.printf("%57s %n", "Main Menu\n");
System.out.printf("%72s %n", "Zoo has the following ticketing options: \n");
System.out.printf("%59s %n", "1 = Child (4-5 yrs)");
System.out.printf("%59s %n", "2 = Adult (18+ yrs)");
System.out.printf("%60s %n", "3 = Senior (60+ yrs)\n");
String choose1 = "";
String choose2 = "";
String choose3 = "";
String selected = "";
int option = 0;
System.out.print("Please select an option: ");
option = input.nextInt();
if (option == 1) {
choose1 = "Child";
selected = choose1;
} else if (option == 2) {
choose2 = "Adult";
selected = choose2;
} else if (option == 3) {
choose3 = "Senior";
selected = choose3;
}
System.out.println(); // "\n" is a redundant argument
int price = 0;
int tickets = 0;
System.out.print("Enter the number of tickets: ");
tickets = input.nextInt();
if (selected.equals(choose1)) { // you should never compare strings with == operator! Always use .equals() instead
price = 10;
} else if (selected.equals(choose2)) {
price = 20;
} else if (selected.equals(choose3)) {
price = 15;
}
System.out.println();
System.out.print("You are purchasing " + tickets + " " + selected + " tickets at " + "$" + price + " each!");
System.out.println();
int confirm = 0;
System.out.print("Press 1 to confirm purchase: ");
confirm = input.nextInt();
if (confirm != 1) {
System.out.print("Incorrect Key. Please return to Main Menu");
System.out.println("\n");
} else {
//break; you cannot use 'break' in the if statement! You have to figure out another way, how to handle an invalid input
}
System.out.println();
int total = tickets;
price = total * price;
System.out.print("Total amount for " + selected + " tickets: " + "$" + price);
System.out.println();
String pick = "";
System.out.print("Do you wish to continue: ");
pick = input.next(); // you have to assign the input to a variable
System.out.println();
if (pick.equals("no")) { // You have to ALWAYS use .equals() when comparing Strings or any other reference types! == works correctly only with primitive types
System.out.print("Total amount payable is: " + "$" + price);
System.out.println();
System.out.print("Have a nice day!");
System.out.println();
break; // you need to break from the loop in the end
}
}
}