java - 未知变量

Question

为什么当我在第二个循环中引用变量 eachLetter 时，它是未知的？

import java.util.*;

public class Main {

    public static void main(String [] args) {
        String myName = ("Yourname");
        int maxLength = myName.length() - 1;
        for (int loops = 0; loops <= maxLength; loops++) {

            char[] eachLetter = myName.toCharArray();

            System.out.print(loops);
            System.out.print(eachLetter[loops]);
        }
        System.out.println("");
        System.out.println("next loop");
        for (int loops = maxLength; loops <= 0; loops--) {
            System.out.print(loops);
            System.out.print(eachLetter[loops]);

        }
    }
}

Answer 1

因为它只存在于第一个循环范围内。您必须在进入第一个循环之前声明它。

char[] eachLetter = new char[maxLength];
for (int loops=0; loops <= maxLength; loops++) {
    eachLetter = myName.toCharArray();
}
for (int loops= maxLength; loops<=0; loops--) {
    (..)
}