NULL integer ?

[newdomingo]

Hi,

the question is probably stupid, but i would like to ask is there any case an integer to be null ?

If yes, how do we examine that?

I mean we have to use something like the code below :

int A;
if(A == NULL){
    //do something
}else{
    //do something else
}

[davidcpp]

as i know NULL is defined 0 .... i mean somewhere in header files is written

#define NULL 0

...so if (A==NULL) is if (A == 0)

[Duthomhas]

There is no "NULL" for integers.

The NULL is a special value because it is not a valid pointer value. Hence, we can use it as a semaphore to indicate that "this pointer does not point to anything (valid)".

All values in an integer are valid, unless your code assumes otherwise.

For example, the std::string::npos value is the largest integer value. It is special because no string can (supposedly) get that long (and be useful).

You can either choose a special value that you will not consider valid, or you can use another boolean variable to track whether or not the integer has meaning.

Hope this helps.