如何跟踪java中if语句中的变量[重复]

Question

我无法跟踪随机数生成器分配的变量。我尝试生成两个不同范围的随机数，并根据更新分数或不更新分数生成的数字，然后根据一组规则告诉用户他们是赢还是输。

我已经附上了下面的代码，所以你可以看到我在说什么，但我基本上需要变量roll1和roll2的帮助，谢谢你的帮助。

import java.util.Random; // import random number class
import java.util.Scanner;  // Import the Scanner class
public class Main
{

public static void main(String[] args) {
    //rules and variables 
    System.out.println("Welcome to lucky dice, the computer will roll 2 dice...");
    //int roller1 = (int )(Math.random() * 10 + 1); //instance of random class
    //int roller2 = (int )(Math.random() * 20 + 2); //instance of random class
    //Random rand = new Random();
    int total = 0;
    int num = 0;
    int max = 11;
    int min = 1;
    int max2 = 21;
    int min2 = 2;
    
    //create a loop to keep rolling until the user wins or looses 
    while (num <= 20 && total >= -50 && total < 150){
        System.out.println("Are you ready to roll?");
        Scanner reply = new Scanner(System.in);  // Create a Scanner object
        String answer = reply.nextLine();
        Random rand = new Random();
        if (answer == "yes"){
            int roll1 = rand.nextInt(max - min) + min;//instance of random clas
            int roll2 = rand.nextInt(max2 - min2) + min2;//instance of random clas
           
            
        }while(roll2 % 2 == 1){
            int roll2 = rand.nextInt(max2 - min2); //instance of random clas
        }if (roll1 > roll2 || roll2 > roll1){
            total = total + roll1 + roll2; //keep track of score and tell user
            System.out.printf("Your roll was: " + roll1, roll2 + ".");
            System.out.printf("Your score is now " + total + ".");
            num = num + 1;
        }else if (roll1 == roll2){
            total = total + roll1 + roll2; //keep track of score and tell user
            System.out.printf("Your roll was: " + roll1, roll2 + ".");
            System.out.printf(" Your score is now " + total + ". ");
            num = num + 1;
        }
    }if (num > 20){
        System.out.println("You lost!");
    }else if (total >= 150){
        System.out.println("You won!");
    }else if (total >= -50){
        System.out.println("You lost!");
    }
        
   
  
}

}

Answer 1

您已经在if块中声明了一个变量。声明上面的变量级别

 ...
    String answer = reply.nextLine();
    Random rand = new Random();
        int roll1 = 0;
        int roll2 = 0;
    if (answer.equals("yes")){
        roll1 = rand.nextInt(max - min) + min;//instance of random clas
        roll2 = rand.nextInt(max2 - min2) + min2;//instance of random clas  
    }...

还是搬到那里去

...
int min = 1;
int max2 = 21;
int min2 = 2;
int roll1 = 0;
int roll2 = 0;
....