这是我的第一个疑问，我对此实在是个菜鸟，而且我的英语也不是最好的，所以首先抱歉，如果有一个傻瓜错误。 问题是我想进行一个for循环，以保存来自控制台的每个用户输入，并将其添加到名为“ Order”的列表中。如果用户正确键入订单，则必须执行此操作，并且必须检查它以了解菜单上是否存在该订单。如果不是这样，我们必须让用户知道情况并询问他/她是否想要菜单上有的东西。同样，在存储在列表中的每个输入之后，我们想询问用户他/她是否想订购更多商品，因此如果是，则必须初始化循环，如果不是，则必须退出循环。 我的代码存在的问题是，无论我在控制台中键入什么内容，循环都会从头到尾完成。 错误在哪里？ 谢谢!!!
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.Scanner;
public class Fase2_final {
public static void main(String[] args) {
// TODO Auto-generated method stub
String[] menu = { "chicken", "steak", "hamburger", "spaghettis", "pizza" };
int[] price = { 10, 15, 20, 5, 12 };
boolean order = true;
for (int i = 0; i < menu.length; i++) {
System.out.println("We have " + menu[i] + " for " + price[i] + "€");
}
int yes = 1;
int no = 0;
Scanner yesOrNo = new Scanner(System.in);
System.out.println("What do you want to eat?");
List<String> Order = new ArrayList<String>();
do {
Scanner inputOrder = new Scanner(System.in);
String userOrder = inputOrder.next().toLowerCase();
for (int j = 0; j < menu.length; j++) {
if (userOrder.equals(menu[j])) {
Order.add(userOrder);
System.out.println("You ordered" + Order + "\nSomething more?" + "\nSay YES with 1 and NO with 0");
} else if (userOrder.equals(menu[j]) == false) {
System.out.println("We don't have this on menu!"
+ "\nDo you want to order another thing that we do have in menu?" + "\nSay YES with 1 and NO with 0");
} else if (yesOrNo.nextInt() == no) {
System.out.println("Order finished!");
}
}
} while (yesOrNo.nextInt() == yes);
}
}```
答案 0 :(得分：1)
不需要每次迭代都重新声明Scanner对象，也不需要具有多个将从同一源读取的Scanner对象。另外，也无需打印“我没有找到！”每次比较。
请考虑以下代码块：
.
.
.
// there is no need to re-declare the Scanner object every iteration, or two scanners
Scanner keyboard = new Scanner(System.in);
do {
String userOrder = keyboard.next().toLowerCase();
// we haven't found the item
boolean found = false;
// integer option (yes or no)
int option;
// do the search
for (int j = 0; j < menu.length; j++) {
// do this if found
if (userOrder.equals(menu[j])) {
// set flag to indicate we found the item
found = true;
// add the order
Order.add(userOrder);
// print out, then read the user's option
System.out.println("You ordered" + userOrder + "\nSomething more?" + "\nSay YES with 1 and NO with 0");
option = keyboard.nextInt();
// consume the NL leftover from the nextInt() call
keyboard.nextLine();
// break out of the for loop since you already found what you're looking for
break;
}
}
// check if you didn't find the item
if (!found) {
// print out
System.out.println("We don't have this on menu!"
+ "\nDo you want to order another thing that we do have in menu?" + "\nSay YES with 1 and NO with 0");
// read if user wants to continue
option = keyboard.nextInt();
// consume the NL leftover from the nextInt() call
keyboard.nextLine();
}
} while (option == yes);
System.out.println("Order finished!");
.
.
.
// close the scanner when you're done
keyboard.close();
.
.
.
答案 1 :(得分：0)
nextInt（）方法一次返回当前输入，如果调用两次，则需要第二个输入。它应该看起来像这样：
do {
Scanner inputOrder = new Scanner(System.in);
String userOrder = inputOrder.next().toLowerCase();
int answer = 0;
for (int j = 0; j < menu.length; j++) {
if (userOrder.equals(menu[j])) {
Order.add(userOrder);
System.out.println("You ordered" + Order + "\nSomething more?" + "\nSay YES with 1 and NO with 0");
} else if (userOrder.equals(menu[j]) == false) {
System.out.println("We don't have this on menu!"
+ "\nDo you want to order another thing that we do have in menu?" + "\nSay YES with 1 and NO with 0");
} else if ((answer = yesOrNo.nextInt()) == no) {
System.out.println("Order finished!");
}
}
} while (yesOrNo.nextInt() == answer);
我希望我回答了你的问题。
答案 2 :(得分：0)
我已经重构了您的代码。尝试在比较工具中查看。
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
public class Fase2_final {
public static void main(String[] args) {
// TODO Auto-generated method stub
String[] menu = { "chicken", "steak", "hamburger", "spaghettis", "pizza" };
int[] price = { 10, 15, 20, 5, 12 };
boolean order = true;
for (int i = 0; i < menu.length; i++) {
System.out.println("We have " + menu[i] + " for " + price[i] + "€");
}
int decision = 0;
int yes = 1;
int no = 0;
Scanner yesOrNo = new Scanner(System.in);
System.out.println("What do you want to eat?");
List<String> Order = new ArrayList<String>();
do {
Scanner inputOrder = new Scanner(System.in);
String userOrder = inputOrder.next().toLowerCase();
for (int j = 0; j < menu.length; j++) {
if (userOrder.equals(menu[j])) {
Order.add(userOrder);
System.out.println("You ordered" + Order + "\nSomething more?" + "\nSay YES with 1 and NO with 0");
} else if (userOrder.equals(menu[j]) == false) {
System.out.println("We don't have this on menu!"
+ "\nDo you want to order another thing that we do have in menu?" + "\nSay YES with 1 and NO with 0");
}
}
decision = yesOrNo.nextInt();
if (decision == no) {
System.out.println("Order finished!");
}
} while (decision == yes);
}
}
完成后始终关闭扫描仪。