Memory Model in C++

Where are the variables stored in the memory?

overall concept

关于 Global Vars

• vars defined outside any functions
• can by shared btw .cpp files
• extern声明

关于 Static Vars

static global variable

• static global variable inhibits access from outside the .cpp file
• so as the static function

static local variable

• static local variable keeps value in between visits to the same function
• is initialized at its first access

上面列举三中变量都在code/data区（静态数据区），程序启动时即分配好。

Pointers to objects

之前学过，略

Defining Reference

• References are a new data type in C++

char c;         // a character
char* p = &c;   // a pointer to c
char& r = c;    // a reference to c

• Declares a new name for an existing object

• Rules of references:

• References must be initialized when created

• Initialization establishes a binding

• Bindings don’t change at run time, unlike pointers

• Assignment changes the object referred-to

• The target of a non-const reference must be an lvalue.

  

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Dynamic memory allocation

• new expression

new int;
new Stash;
new int[10];

• delete expression

delete p;
delete [] p;

为什么在已经有 malloc / free 的基础上还要 new / delete?

Answer: new \ delete 在分配\释放内存的同时，还会对所声明的数据类型进行初始化 （调用它的Constructor和Destructor）

Const