Java Output Variable Scope Issue

Question

I have an issue regarding variable scope in the following piece of code. Can someone give a quick overview as to why java "cannot find the symbol" for output when it is printed? Thanks.

class Main
{
    public static void main(String[] args) {
        String text = "hello";
        if (text.indexOf(" ") == -1) //if a space doesn't exist
        {
            String output = "one word";
        }
        else
        {
            String output = "more than one word";
        }
        System.out.println(output);
    }
}

Answer 1

变量output 仅存在于当前包含在if块和else块中的包含代码块中，如果要访问if和else块之外的变量output ， if需要在if之前定义它块。

Answer 2

Local variables

A local variable is the one that is declared within a method or a constructor (not in the header). The scope and lifetime are limited to the method itself.

In addition to the local variables defined in a method, we also have variables that are defined in blocks, eg the if block and an the else block. The scope in this case is constrained by the block itself.