diff --git a/README_en.md b/README_en.md
index 9ff2de5..ef6a2e6 100644
--- a/README_en.md
+++ b/README_en.md
@@ -127,6 +127,17 @@ const int* function6();     // returns a pointer variable to a constant, use: co
 int* const function7();     // returns a constant pointer to a variable, use: int * const p = function7 ();
 ```
 
+#### #define and const constants 
+
+#define|const constants
+---|---
+Macro definitions, equivalent to character substitution|constant declarations
+preprocessor processing|compiler processing
+without type safety checking|with type safety checking
+no memory allocation|memory allocation required
+stored in code segment|stored in data segment
+Can be canceled by `#undef`|Not cancelable
+
 ### static
 
 #### Function
diff --git a/docs/README.md b/docs/README.md
index 3e3a384..8f000ce 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -115,6 +115,17 @@ const int* function6();     // 返回一个指向常量的指针变量，使用
 int* const function7();     // 返回一个指向变量的常指针，使用：int* const p = function7();
 ```
 
+#### 宏定义 #define 和 const 常量 
+
+宏定义 #define|const 常量
+---|---
+宏定义，相当于字符替换|常量声明
+预处理器处理|编译器处理
+无类型安全检查|有类型安全检查
+不分配内存|要分配内存
+存储在代码段|存储在数据段
+可通过 `#undef` 取消|不可取消
+
 ### static
 
 #### 作用
diff --git a/docs/en.md b/docs/en.md
index 68336b3..91dac88 100644
--- a/docs/en.md
+++ b/docs/en.md
@@ -120,6 +120,17 @@ const int* function6();     // returns a pointer variable to a constant, use: co
 int* const function7();     // returns a constant pointer to a variable, use: int * const p = function7 ();
 ```
 
+#### #define and const constants 
+
+#define|const constants
+---|---
+Macro definitions, equivalent to character substitution|constant declarations
+preprocessor processing|compiler processing
+without type safety checking|with type safety checking
+no memory allocation|memory allocation required
+stored in code segment|stored in data segment
+Can be canceled by `#undef`|Not cancelable
+
 ### static
 
 #### Function