每次进行计算时，如何打印出我的 RPN 计算器堆栈？

如何解决每次进行计算时，如何打印出我的 RPN 计算器堆栈？

我希望这个问题很容易回答，但是我在制作 RPN 计算器时遇到了问题，我希望程序每次进行计算时都打印出“答案”，而不必指定结束文件 (Ctrl + Z) 以查看计算结果。对于上下文，这是我正在使用的代码：

import java.util.Scanner;


public class McIntyreJLab3 {
    
    public static void main (String args[]) {
        processInput rpninput = new processInput();
    }
}//McIntyreJLab1

class processInput {

    processInput() {
        
        double doubleval = 0;
        int charval = 0;
        String ident = "";
        Stack stack = new Stack();
        
        Scanner in = new Scanner (System.in);
        
        System.out.println("Please enter your input into the command line,then once you have submitted your input,please type Ctrl + Z signify you have finished your input.");
        
        while (in.hasNext()) {
            if (in.hasNextDouble()) {
                doubleval = in.nextDouble();
                System.out.println(doubleval + ": Double");
                stack.push(doubleval);
            } else {//if there is a double at the current placeholder on the input
                ident = in.next();
                charval = (int) ident.charAt(0);
                if(charval == 42|| charval == 43 || charval == 45 || charval == 47) {
                    System.out.println(ident + ": Operator");
                    double v1 = stack.pop();
                    double v2 = stack.pop();
                    switch (charval) {
                    
                    case 42:
                        v2 = v2 * v1;
                        stack.push(v2);
                        break;
                    case 43:
                        v2 = v2 + v1;
                        stack.push(v2);
                        break;
                    case 45:
                        v2 = v2 - v1;
                        stack.push(v2);
                        break;
                    case 47:
                        v2 = v2 / v1;
                        stack.push(v2);
                        break;
                    default: 
                        System.out.println("That is not an acceptable operator");
                        break;
                    }
                } else { //checking for operators
                    System.out.println(ident + ": Identifier");
                }//since no operator was found,it is an identifier
            }//else statement for operators
            
        }//loop for taking in the input and categorizing it into: identifier,operator,or double.
        
        System.out.println("End of Line Reached");
        double result = stack.pop();
        
        if (!stack.isEmpty()) {
            System.out.println("Too many operators or doubles");
            System.exit(0);
        } else {
            System.out.println(result);
        }
       
    }//processInput method
}//processInput class

class Stack {
    
    private int stack_capacity = 100;
    private int tos = -1;
    private double[] my_stack = new double[stack_capacity];
    
    public void push(double item_to_push) {
        
        if (tos + 1 >= stack_capacity) {
            System.out.println("Exceeded Capacity");
            System.exit(0);
        }//checking if the stack will overflow
        tos++;
        my_stack[tos] = item_to_push;
    }//pushing doubles into the stack
    
    public double pop() throws NullPointerException {
        if (tos < 0) {
            System.out.println("Stack is empty");
            System.exit(0);
        }//if the stack is empty
        double v = my_stack[tos];
        tos--;
        return v;
    }//pop a value
    
    public boolean isEmpty(){
          return tos == -1;
    }
    
    
}//Stack

为了快速总结一下这段代码目前的作用（你也可以自己尝试），它本质上要求值和运算符以反向波兰符号格式执行计算，问题是，在为了获得答案，您必须按 Ctrl + Z，然后输入以指定文件结尾，该文件将显示答案，但也会阻止用户输入更多值。假设用户想要继续计算已经输入的内容，我需要做什么才能允许用户继续输入值和运算符？如果有人可以帮助我，那就太好了！