增加转换函数

.gitignore

@@ -1,3 +1,4 @@
 chapter_8/a.out
 chapter_8/carinfo.txt
 chapter_9/a.out
+chapter_10/a.out

chapter_10/file.cpp

@@ -88,3 +88,22 @@ std::ostream & operator<<(std::ostream & os, const Stock & s)
          << "_b: " << s._b << endl << endl;
     return os;
 }
+
+Stock::operator int () const
+{
+    cout << "operator int () const\n";    
+    return 1;
+}
+
+Stock::operator double () const
+{
+    cout << "operator double () const\n";    
+    return 2.0;
+}
+
+
+Stock::operator char () const
+{
+    cout << "operator char () const\n"; 
+    return 'h';
+}

chapter_10/header/file.h

@@ -20,16 +20,23 @@ class Stock
 public:
     Stock();
     Stock(double n);
-    explicit Stock(int n);
+    explicit Stock(int n); //显示初始化
 
     Stock(const std::string & co, double a1 = 1, double b1 = 0);
     ~Stock();
+
     void show(void) const; //当定义常量的类时，可以调用该方法
     const Stock & topval(const Stock & s) const;
+
     Stock operator+(const Stock & s) const; //重载加法
     Stock operator*(double m) const; //重载乘法
+
     friend Stock operator*(double m,  const Stock & n); //重载超过一个参数，则只能写成友元函数
     friend std::ostream & operator<<(std::ostream & os, const Stock & s); 
+
+    operator int () const; //转换函数
+    operator double () const;
+    explicit operator char () const;
 };
 
 #endif

chapter_10/main.cpp

@@ -18,13 +18,17 @@ void class_test(void);
 void class_this_test(void);
 void class_operator_test(void);
 void friend_test(void);
+void convert_function_test(void);
+
 
 int main(int agrs, char *argv[])
 {
-	class_test();
+	// class_test();
 	// class_this_test();
  	//class_operator_test();
 	//friend_test();
+	convert_function_test();
+
 
 	cin.get();
 	cin.get();
@@ -132,4 +136,16 @@ void friend_test(void)
 	}
 }
 
+//转换函数，将类对象赋值给其他类型
+void convert_function_test(void)
+{
+	Stock stock1("Lee", 1, 1);
+	int a = stock1;
+	double b = stock1;
+
+	// long c = stock1; //有二意性，编译报错
+	long d = (int) stock1; //指定转换函数
 
+	// char e = stock1; //explicit声明，必须加显示使用显示转换
+	char e = (char)stock1;
+}