support bazel complie this project and format code.

basic_content/volatile/BUILD

@@ -0,0 +1,15 @@
+# please run `bazel run basic_content/volatile:noopt_vola`
+# please run `bazel run basic_content/volatile:volatile`
+load("@rules_cc//cc:defs.bzl", "cc_binary")
+
+cc_binary(
+    name = "noopt_vola",
+    srcs = ["noopt_vola.cpp"],
+    copts = ["-std=c++11"]
+)
+
+cc_binary(
+    name = "volatile",
+    srcs = ["volatile.cpp"],
+    copts = ["-std=c++11"]
+)

basic_content/volatile/README.md

@@ -80,7 +80,7 @@ void threadFunc2()
 可以。一个例子是只读的状态寄存器。它是volatile因为它可能被意想不到地改变。它是const因为程序不应该试图去修改它。
 
 （2）一个指针可以是volatile吗？为什么？
-可以。尽管这并不常见。一个例子是当一个中断服务子程序修该一个指向一个buffer的指针时。
+可以。尽管这并不常见。一个例子是当一个中断服务子程序修改一个指向一个buffer的指针时。
 
 （3）下面的函数有什么错误？
 ```c++

basic_content/volatile/noopt_vola.cpp

@@ -1,15 +1,14 @@
 /* Compile code without optimization option */
-#include <stdio.h> 
-int main(void) 
-{ 
-    const int local = 10; 
-    int *ptr = (int*) &local; 
+#include <stdio.h>
+int main(void) {
+  const int local = 10;
+  int *ptr = (int *)&local;
 
-    printf("Initial value of local : %d \n", local); 
+  printf("Initial value of local : %d \n", local);
 
-    *ptr = 100; 
+  *ptr = 100;
 
-    printf("Modified value of local: %d \n", local); 
+  printf("Modified value of local: %d \n", local);
 
-    return 0; 
-} 
+  return 0;
+}

basic_content/volatile/volatile.cpp

@@ -1,16 +1,15 @@
 /* Compile code with optimization option */
-#include <stdio.h> 
+#include <stdio.h>
 
-int main(void) 
-{ 
-    const volatile int local = 10; 
-    int *ptr = (int*) &local; 
+int main(void) {
+  const volatile int local = 10;
+  int *ptr = (int *)&local;
 
-    printf("Initial value of local : %d \n", local); 
+  printf("Initial value of local : %d \n", local);
 
-    *ptr = 100; 
+  *ptr = 100;
 
-    printf("Modified value of local: %d \n", local); 
+  printf("Modified value of local: %d \n", local);
 
-    return 0; 
-} 
+  return 0;
+}