update

basic_content/virtual/set2/default_arg.cpp

@@ -0,0 +1,39 @@
+/**
+ * @file first_example.cpp
+ * @brief 虚函数中默认参数
+ * 规则：虚函数是动态绑定的，默认参数是静态绑定的。默认参数的使用需要看指针或者应用本身的类型，而不是对象的类型！
+ * @author 光城
+ * @version v1
+ * @date 2019-07-24
+ */
+
+#include <iostream> 
+using namespace std; 
+
+class Base 
+{ 
+    public: 
+        virtual void fun ( int x = 10 ) 
+        { 
+            cout << "Base::fun(), x = " << x << endl; 
+        } 
+}; 
+
+class Derived : public Base 
+{ 
+    public: 
+        virtual void fun ( int x=20 ) 
+        { 
+            cout << "Derived::fun(), x = " << x << endl; 
+        } 
+}; 
+
+
+int main() 
+{ 
+    Derived d1; 
+    Base *bp = &d1; 
+    bp->fun();  // 10
+    return 0; 
+} 
+