Static Member in C++ Language

Static Member in C++ 

There are three types of Static Member in C++ Language:-

1- Static Local Variables

2- Static Member Variables

3- Static Member Functions

1- Static Local Variables

Example of Static Local Variables

static local variable

Here in above example,'static int x' means static local variable which by default value will be zero and 'int y' by default value will be garbage.When fun() is call then 'y' variable get value

and after the work of fun() finished then the value of 'y' will destroy but the variable of 'x' 

 get value from the beginning of program  which remains until the end of the program.

2- Static Member Variables

Example of Static Member Variables

static member variable

In above example , 'int balance' is called Instance Member Variable where as static float roi(rate

of interest) is called Static Member Variable or we can say Class Variable. When we make 'Account'

class object -a1,a2 which has only one variable i.e int balance and 'roi' variable is not the part of object therefore it's exit whether you made any object like a1,a2 or not but you have to declared

'roi' variable outside the class as we seen in above example..

3- Static Member Functions

Here in above example, we can't access 'roi' variable in 'main ()' because it is private member so if want to access' roi' in 'main ()' function then we have to make function in class i.e 'void setRoi(float r)' where r recieve float type value as we seen in above example but remember here 'setRoi()' function  access by an object (a1) of class(Account) but we know that static member call directly without any object so we have to make' setRoi ()' function  as Static Member Function as we see in below:--

static member function

Here we seen that to make setRoi as Static Member Function, we used Static keyword before
setRoi() function as 'Static void setRoi (float r)' . Now, we can directly access 'setRoi()' function
in 'main ()' function i.e Account(class name)::(scope revolution)setRoi(4.5f)(function name) of as we seen in above..

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