What is a null pointer in D?
Overview
A pointer is an address that points or references a variable in memory. In D programming, we allocate dynamic memory using pointers. The pointer references the address of the variable, unlike the usual direct referencing of the variable itself.
What is a null pointer?
A null pointer indicates that the address that has been referenced is invalid. Most operating systems have 0 reserved as a system address inaccessible by other programs.
A null pointer is important because it saves memory and reduces uninitialized spaces. Let's look at a good example.
Example
import std.stdio;void main () {int sed = 5;int *pointer = &sed;int *nullpointer = null;writeln("The value of pointer is " , pointer) ;writeln("The value of pointer is " , nullpointer) ;}
Code explanation
- Line 4: We declare a variable
sedand assign a value to it. Pointers reference the address of a variable.
- Line 5: We get the pointer of the
sedvariable
- Line 6: We create a
nullpointer callednullpointer.
- Line 8: We print the pointer of the
sedvariable to the screen. This is the storage location/address of thesedvariable.
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