C ++ basic function code example

Many important functions in the C ++ programming language play a very important role in our actual program development. Here we will summarize three commonly used basic C ++ functions. You can have a comprehensive understanding of the functions in C ++ programming language.

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When talking about destructor, almost all reference books around me use only a little space without exception, but Big C ++ is really rare to hit the key once

Quality tip 18.4: if there is a destructor, there should also be three basic functions: copy constructor and assign value operator)

For classes that manage heap memory, these three functions must be implemented

Example:

 
 

  
  
// A non-standard String class of the string class, which is a class created by an individual. No copy constructor is defined.
  
  
String a = "GG"; // allocate a heap
  
  
Local scope {
  
  
String B = a; // error. a shared heap is generated when copying by members.
  
  
} // The local scope ends and the Destructor B. ~ Is called .~ String (), the heap space is deleted
  
  
// At this time, the heap space of a has been deleted by the destructor of B.
 
 

Common construction modes:

Copy constructor of C ++ basic functions

 
 

  
  
X::X (const X& right){  
  
  
copy(right);  
  
  
} 
 
 

Value assignment operator overloading for C ++ basic functions

 
 

  
  
X& X::operator=(const X& right){  
  
  
if (this !=&right){  
  
  
free();  
  
  
copy(right);  
  
  
}  
  
  
return *this;  
  
  
} 
 
 

Analysis of C ++ basic functions
 

 
 

  
  
X::~X(){  
  
  
free()  
  
  
}