I'm going to go out on a limp here, and guess you mean "Null Pointer." Well, it's a pointer to nothing. For most systems, it's 0, but rather use NULL instead.
Because the null character represents the end of the string.
Every programming language treats strings as arrays. A C string is defined as being a null-terminated array of characters. A C string that does not have a null-terminator is just an array of character values, but without a null-terminator the onus is upon the programmer to keep track of the array's length.
In C programming language, a string is an array of characters which is always terminated by a NULL character: '\0'
Using a NULL macro to make C portableI'll assume that you're asking your question for C type language programming. A NULL pointer is a pointer that's guarnteed to point to nothing. This may be 0 in a UNIX/Linux system or some other address in another system. Using the NULL macro to set/initialize your pointers will make your programs more portable among systems than using something like the 0.#include char *c = 0; // initialize to NULL--not portablechar *p = NULL; // initialize to NULL as defined in stdio is portableAddendumThe code:char *c = 0;actually is portable because the compiler converts 0's used in a pointer context (cast to a pointer) to the machine's representation of a NULL pointer, which may or may not be all 0 bits. The NULL macro itself might be defined as something like 0 or (void *)0, and both definitions are portable. As a corollary, the following code is also portable:if (!c) {// do something}because it is equivalent to:if (c != 0) {// do something}and the 0 above is converted to a NULL pointer because it is being compared with a pointer.
its just an programming error in farmville .it would soon be alright null definition in Programming : A special value used in several languages to represent the thing referred to by an uninitialised pointer/database
its just an programming error in farmville .it would soon be alright null definition in Programming : A special value used in several languages to represent the thing referred to by an uninitialised pointer/database
its just an programming error in farmville .it would soon be alright null definition in Programming : A special value used in several languages to represent the thing referred to by an uninitialised pointer/database
ts just an programming error in farmville .it would soon be alright null definition in Programming : A special value used in several languages to represent the thing referred to by an uninitialised pointer
Pointer is a variable that stores address of a variable . A NULL Pointer a pointer that doesn't point to anything, it is a literal zero .Some people ,notably C++ programmers, prefer to use 0 rather than NULL.
From a C-program?ShellExecute (NULL, "open", "C:\DIR\INDEX.HTML", NULL, NULL, SW_SHOW);
A pointer variable which is declared but not initialized is called a NULL POINTER.ex: int *p;Please don't use the above. A NULL pointer is a specific value assigned to a pointer, just like any other value. NULL is a language-specific designation, and is guaranteed to be comparable to, unlike uninitialized variables, which can have any value.That is:int *a;int *b = NULL;int *c = (int *) malloc(sizeof(char));( a c) is NEVER true.NULL is a reserved word in most high-level languages, and indicates a specific value for assignment. It is commonly used to indicate that something has not yet been assigned a "real" value, or has had its contents deleted. It is an EXPLICIT value, and not just "undefined".In the context of pointers (which, remember, are really memory location addresses), a NULL pointer is one which has NO value, and thus does NOT point to any memory location. The difference between an uninitialized pointer and a NULL pointer is that most common languages do not specify what value an uninitialized pointer has upon creation (many, such as C, are assigned a random value), while a NULL pointer explicitly has NO value (which is the meaning of NULL).Many modern languages and compilers will assign NULL to a pointer upon initialization, but don't count on it. It is sloppy programming to do so, and can lead to many hard-to-find errors.
ts just an programming error in farmville .it would soon be alright null definition in Programming : A special value used in several languages to represent the thing referred to by an uninitialised pointer