为什么我不能访问在开关中声明的变量？

Question

this is my code : there is a probléme "can't acces to variable j"

public static void main(String args[]) { 
    char digit = 'a';
    for (int i = 0; i < 10; i++){ 
        switch (digit){ 
            case 'x' : { int j = 0; System.out.println(j); } 
            default : { int j = 100; System.out.println(j); }

        }
    }
    int i = j;
    System.out.println(i); 
}

Answer 1

Each variable has scope. Scope is a restriction regarding where some variable can be accessed.

When you declare a variable in any type of block {} , that variable can only be accessed within that block of code.

You'll have to declare (and possibly initialize) the variable outside the block so its scope is greater, either at the method level or as a static variable (or instance if you were working with instance methods).