support bazel complie this project and format code.

basic_content/const/class_const/first_example/BUILD

@@ -0,0 +1,16 @@
+# please run `bazel run basic_content/const/class_const/first_example:main`
+load("@rules_cc//cc:defs.bzl", "cc_binary", "cc_library")
+
+cc_library(
+    name = "apple",
+    srcs = ["apple.cpp"],
+    hdrs = ["apple.h"],
+)
+
+cc_binary(
+    name = "main",
+    srcs = ["main.cpp"],
+    deps = [
+        ":apple",
+    ],
+)

basic_content/const/class_const/first_example/apple.cpp

@@ -1,13 +1,20 @@
-class Apple
-{
-private:
-    int people[100];
-public:
-    Apple(int i);
-    const int apple_number;
-    void take(int num) const;
-    int add(int num);
-    int add(int num) const;
-    int getCount() const;
-};
+#include "apple.h"
+#include <iostream>
 
+Apple::Apple(int i) : apple_number(i) {}
+int Apple::add(int num) {
+  take(num);
+  return 0;
+}
+int Apple::add(int num) const {
+  take(num);
+  return 0;
+}
+void Apple::take(int num) const {
+  std::cout << "take func " << num << std::endl;
+}
+int Apple::getCount() const {
+  take(1);
+  //    add(); //error
+  return apple_number;
+}

basic_content/const/class_const/first_example/apple.h

@@ -0,0 +1,11 @@
+#pragma once
+
+class Apple {
+public:
+  Apple(int i);
+  const int apple_number;
+  void take(int num) const;
+  int add(int num);
+  int add(int num) const;
+  int getCount() const;
+};

basic_content/const/class_const/first_example/main.cpp

@@ -1,32 +1,12 @@
-#include<iostream>
-#include"apple.cpp"
+#include "apple.h"
+#include <iostream>
 using namespace std;
 
-Apple::Apple(int i):apple_number(i)
-{
-
-}
-int Apple::add(int num){
-    take(num);
-}
-int Apple::add(int num) const{
-    take(num);
-}
-void Apple::take(int num) const
-{
-    cout<<"take func "<<num<<endl;
-}
-int Apple::getCount() const
-{
-    take(1);
-//    add(); //error
-    return apple_number;
-}
-int main(){
-    Apple a(2);
-    cout<<a.getCount()<<endl;
-    a.add(10);
-    const Apple b(3);
-    b.add(100);
-    return 0;
+int main() {
+  Apple a(2);
+  cout << a.getCount() << endl;
+  a.add(10);
+  const Apple b(3);
+  b.add(100);
+  return 0;
 }