Thinking about C ++ functions 1 (the default six functions), the default six

Thinking about C ++ functions 1 (the default six functions), the default six

We know that when designing C ++, the great gods will have six default functions for C ++. The so-called default is that we don't need to write them, when you instantiate a class, that is, creating an object, the compiler automatically calls the default function when using the object for data operations, however, the default functions are not intended for use by C ++. What is really powerful is that we are based on these default functions, DIY functions can achieve what default functions cannot do and what they can do. Only in this way can you increase your skill. The following are some of my thoughts when writing C ++ functions:

The six default functions are as follows:

<Pre name = "code" class = "cpp"> /************************** **************************************** * ***** Copyright (c) 2015, WK Studios ** Filename: str. h ** Compiler: GCC vc 6.0 ** Author: WK ** Time: 2015 31 5 ************************************* * *********************************/class S {public: S (int I = 0, double n = 0): m_data (I), data (n) {cout <this <"\ n";} private: int m_data; double data ;}; int main () {S s0; // 1 // The default no-argument constructor will no longer be called by the UDF compiler, // to do this, you must define a non-argument constructor or a custom default constructor. // just like the above function, that is, if there is a default value, an error is reported because the corresponding constructor S (10) is not found; // 2 S (10.8); // 3 S (int) 10.8 ); // 4S ss (10, 20); // 5S ss1 (10.8); // 6 S ss2 (int) 10.8); // 7 S (10, 10.8 ); // 8 // call the constructor S s22 = (10, 10.8); // 9 S s1 = (10, 10.8); // 10

// Six Default functions of C ++ // those functions are transparent when used, that is, those functions have learned a trick of stealth technology. Hahaha, class Default {public: /* Default () {}// Default constructor Default (const Default &) {}// copy constructor ~ Default () {}// destructor Default & operator = (const Default &) {}// value assignment operator Default * operator &() {}// accessors const Default * operator & () const {}// accessors */private: int m_Data ;}; int main () {Default t; // call the constructor Default t1 = t; // Default t1 (t); // call the copy constructor Default t2; t2 = t; // call the value assignment function Default * pt = & t; // call the value function const Default t3; const Default * pt1 = & t3; // call the const value function // call the Destructor return 0 ;}

The strength of C ++ is not how many default encapsulation methods are available, but the greatest space for programmers to create on the basis of satisfying these basic functions. These default functions can only ensure the normal mode of C ++. On this basis, there is a great space for interface design and implementation.

1. Let's look at a program.