add scope

data/1.Java初阶/5.Java中的变量与常量/3.Java中的常量/config.json

 {
   "node_id": "569d5e11c4fc5de7844053d9a733c5e8",
-  "keywords": [],
+  "keywords": ["常量", "定义", "变量", "final"],
   "children": [],
   "export": ["solidity.json"]
 }
\ No newline at end of file

data/1.Java初阶/5.Java中的变量与常量/4.变量的作用域/config.json

+{
+  "node_id": "db24c3ffc1f04d9e9a61083364091d82",
+  "keywords": ["常量", "定义", "作用域"],
+  "children": [],
+  "export": ["scope.json"]
+}
\ No newline at end of file

data/1.Java初阶/5.Java中的变量与常量/4.变量的作用域/scope.json

+{
+    "type": "code_options",
+    "author": "刘鑫",
+    "source": "scope.md",
+    "exercise_id":"009d35ca11a24baa809d0eeb5e2f66e2"
+}
\ No newline at end of file

data/1.Java初阶/5.Java中的变量与常量/4.变量的作用域/scope.md

+# 作用域
+
+下面选项中，输出为 100 的是。
+
+## 答案
+
+```java
+
+public class Square {
+    private int x = 10;
+    public int area() {
+        return x * x;
+    }
+}
+
+// place in anywhere runnable 
+
+System.out.println(new Square().area())
+
+```
+
+## 选项
+
+### 无法访问到 x
+
+```java
+
+public class Square {
+    private int x = 10;
+}
+
+// place in anywhere runnable 
+
+System.out.println(x*x)
+
+```
+
+### x 已经被修改
+
+```java
+
+int x = 10;
+x = x * 2;
+
+System.out.println(x*x)
+
+```
+
+### 内部作用域的局部变量从外部无法访问
+
+```java
+
+
+public void process() {
+    int x 100;
+}
+
+process()
+
+System.out.println(x)
+
+```
+
+### x 值在程序运行的过程中被修改
+
+```java
+
+x = 100;
+
+for(int i = 0; i < 10 ; i++){
+    x = x + 5;
+}
+
+System.out.println(x)
+
+```
\ No newline at end of file