diff --git a/book/en-us/02-usability.md b/book/en-us/02-usability.md
index c5a4cd8..00e3588 100644
--- a/book/en-us/02-usability.md
+++ b/book/en-us/02-usability.md
@@ -53,8 +53,7 @@ void foo(char *);
 void foo(int);
 
 int main() {
-    if (std::is_same<decltype(NULL), decltype(0)>::value ||
-        std::is_same<decltype(NULL), decltype(0L)>::value)
+    if (std::is_same<decltype(NULL), decltype(0)>::value)
         std::cout << "NULL == 0" << std::endl;
     if (std::is_same<decltype(NULL), decltype((void*)0)>::value)
         std::cout << "NULL == (void *)0" << std::endl;
diff --git a/book/zh-cn/02-usability.md b/book/zh-cn/02-usability.md
index 6b82dc2..1d30be4 100644
--- a/book/zh-cn/02-usability.md
+++ b/book/zh-cn/02-usability.md
@@ -43,8 +43,7 @@ void foo(char *);
 void foo(int);
 
 int main() {
-    if (std::is_same<decltype(NULL), decltype(0)>::value ||
-        std::is_same<decltype(NULL), decltype(0L)>::value)
+    if (std::is_same<decltype(NULL), decltype(0)>::value)
         std::cout << "NULL == 0" << std::endl;
     if (std::is_same<decltype(NULL), decltype((void*)0)>::value)
         std::cout << "NULL == (void *)0" << std::endl;
diff --git a/code/2/2.01.nullptr.cpp b/code/2/2.01.nullptr.cpp
index 9b8c80a..8fc1763 100644
--- a/code/2/2.01.nullptr.cpp
+++ b/code/2/2.01.nullptr.cpp
@@ -14,8 +14,7 @@ void foo(char *);
 void foo(int);
 
 int main() {
-    if (std::is_same<decltype(NULL), decltype(0)>::value ||
-        std::is_same<decltype(NULL), decltype(0L)>::value)
+    if (std::is_same<decltype(NULL), decltype(0)>::value)
         std::cout << "NULL == 0" << std::endl;
     if (std::is_same<decltype(NULL), decltype((void*)0)>::value)
         std::cout << "NULL == (void *)0" << std::endl;