Explain pointer with the help of an example?

Answer 1

Pointers are data types that hold integer values, those "integer" values are simply addresses of another variables.



Example:

int x = 15; // this is an integer variable with value 15

int* ptr; // this is a pointer to an integer

ptr = &x; // now we assigned the address of x to the pointer ptr

// if you want to access the value of x (15 in this example),
// you should use the deterrence *

// so you can say:
printf("%d", *ptr); // this will print 15

// you can print the value of ptr (which is the address of x) using:

printf("%p", ptr); // this will print an integer, which is the address of x.



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More explanation, let's imagine that this is a memory:

-00--01-02-03-04 =====> these are the address of the memory
|--- |--- |---|---|---| =====> values inside the memory


For the example I gave before, let's imagine the following:

-00-01-02--03--04
|---|15|--- | 01 |---|
------x------- ptr


As you can see, x hold the value 15, ptr holds the value 01 which is actually the address of x. Now ptr have a distinct address too, which is 03.

In reality, the address of a memory is longer, and usually represented as hexadecimal values. example 0x002154

You can find more information here:
http://en.wikipedia.org/wiki/Pointers

Answer 2

A pointer is a variable that stores a memory address.

int x = 10;

int * p = &x;

Here, an integer, x, is allocated and assigned the value 10, while p is assigned the memory address of that integer. Note that since x is a reference, we can reassign p without creating a memory leak.

p = new int(10);

Here, p is assigned the memory address of a new integer which is assigned the value 10. However, the new integer is not referenced, therefore we cannot reassign p before releasing the integer it points to. If we reassign p without releasing this memory, we'll have a memory leak.

delete( p );

Answer 3

Pointer is an address (or a variable holding an address). Scale factor is something completely unrelated.

Answer 4

z=*ptr+2 is the statement is true