您好，编码专家们。这里只是一个菜鸟，目前卡在泡菜中。 我正在编写一个数学训练程序，并且需要循环回到我的主菜单。 有一个无限循环，我很难摆脱。如果用户一直在回答正确的答案，那么它只会继续问另一个问题。选择是将生成一个新答案，并将继续这样做（无限）。选择否将终止程序。 如果他们选择“否”，我该如何使用户回到主菜单？ 另外，如果他们选择“是”，那么如何使该问题最多循环一个新方程式10次，然后再将用户带回到我的主菜单。
这是我的代码：
import java.util.Scanner;
import java.util.Random;
public class MathPracticeProgram
{
public static void main(String[] args)
{
//Scenario: Make a practice program for Addition, Subtraction, Multiplication, and Division. Include exit option as well.
Random rand = new Random ();
Scanner scan = new Scanner (System.in);
int menu = (5);
int num1, num2, user_answer, total;
System.out.println("Math Practice Porgram");
System.out.println("Please Input Your Choice via the number\n");
System.out.println("1. Addition\n2. Subtraction\n 3. Multiplication\n 4. Division\n Exit Program by entering 0");
System.out.println("\nYour choice:");
menu = scan.nextInt();
System.out.println("\n");
//Menu Selection
if (menu <= 5 || menu > 0)
{
switch(menu)
{
//Exit
case 0:
{
System.out.println("Thank you for using my math practice program.");
}
break;
//Addition
case 1:
{
System.out.println("You have selected Addition");
String user_again;
do
{
num1 = rand.nextInt(99);
num2 = rand.nextInt(99);
int counter = 0;
do
{
System.out.println("New solution to solve: ");
System.out.println(num1 + " + " + num2 + " = ");
user_answer = scan.nextInt();
System.out.println("\n");
total = num1 + num2;
if(user_answer != total)
{
System.out.println("Incorrect...");
counter++;
}
}while (user_answer != total && counter < 3);
System.out.println("Correct! Do you want another problem? yes or no: ");
user_again = scan.next();
}while(user_again.equalsIgnoreCase("yes"));
System.out.println("\nChanging to Main Menu\n");
}
break;
//Subtraction
case 2:
{
}
break;
//Multiplication
case 3:
{
System.out.println("Multiplication");
}
break;
//Division
case 4:
{
System.out.println("Division");
}
break;
}
}
}
}