i want to full detail of pointer concept.
means how can i access pointer in my programs?
why pointer is always consume 2 bytes? and what is the main concept behind the double pointer?
A pointer is a variable that holds the address of a memory location. This may or may not be the address of another variable or a piece of allocated memory. often specify what type of thing it is that the pointer is pointing to, however it is possible to specify a pointer that points at anything.
A pointer is not always 2 bytes. In fact on most of the systems I have used pointers have been 4 bytes, however I have used a system where pointers where either 2 or 4 bytes depending on how they were declared. The size of a pointer is not specified by C it is platform (machine and compiler) dependent.
Pointers are useful anywhere where you wish to pass a reference to an object, they are also integral to using dynamically allocated memory because malloc (or new) returns a pointer to the allocated memory.
If by double pointer you mean a pointer to pointer, this is useful anywhere where you want to reference a pointer.