知道为什么不能将 `ichoice` 解析为变量吗？

Question

I'm trying to write a do while loop to print out a menu until choice 5 is entered.

I have declared my variable ichoice as an integer and have not had any problems with it until my last line of code. Its taken me a while to get to this point so very confused as to why it wont work!

import java.util.Scanner;

public class testCoinSorter {
    
    public static void main(String[] args) {
        //An example
        
        CoinSorter exampleOne = new CoinSorter("Pound Sterling (£)", 0, 10000, new int[] {10,20,50,100,200});
        
    
        //System.out.println(1);
        do {
            System.out.println("Choice 1 - Coin Calculator");
            System.out.println("Choice 2 - Multiple coin calculator");
            System.out.println("Choice 3 - Print coin list");
            System.out.println("Choice 4 -- display program configurations");
            System.out.println("Choice 5 - quit the program & save the data");
            Scanner in = new Scanner(System.in);
            int ichoice;
            ichoice = in.nextInt();
            switch(ichoice) {
                case 1:
                          // put code for enrolling a new student here
                          System.out.println("Enrolling a new student");
                          // etc etc
                    break;
                case 2:
                    // put code for entering a students mark here
                    System.out.println("Enter the students mark");
                    // etc etc
                    break;
                case 3:
                    // put code for printing out results here
                    System.out.println("Printing out results");
                    // Etc etc
                    break;
                case 4:
                    // put code for calculating final grade here
                    System.out.println("printing final grade");
                    // etc etc
                    break;
                default:
                    if(ichoice != 5) System.out.println("Unknown option");
                    // no need for a break
            } // End of the switch statement
        } while (ichoice != 5);
        
        
    }
}

Any clarification would be greatly appreciated

Answer 1

ichoice variable is defined inside the do-while loop. This makes the variable available only within the do-while loop block scope (which is defined by the { } braces).

To make it accessible in the while ( ) test expression you should move ichoice outside of the loop body eg before the do .