我的非成员静态函数允许更改和创建非静态变量

Question

this is the code snippet

static chck()//tracking how many times main has been called
{
    static a=0;
    int y=0;//this is not supposed to work
    cout<<"Total time main has been called:  ";
    a++;
    return a;
}

our teacher told us that static functions can't change or create non static variables but it works for me ,why?

Answer 1

In this case "y" is a stack variable which this function can access.

The theory is static member functions (static Methods in a class) cannot access non static member variables (non static variables in the class) as there is no object as "this" inside a static member function.

Answer 2

static may well be the most overused keyword in c++. Your first use of it refers to the linkage of chck() , ie it has internal linkage. Your second use makes a static with respect to calls to ckch() , ie it's value will be preserved between calls. You are think of static member functions of a class that can't access non- static data members, ie those data members that are created per object instance.