35. Introduction to Pointer and Arrays

Pointer and arrays:

1. Array elements are always stored in contiguous memory location.

2. A pointer when incremental always pointer to an immediately next location of its type.

Suppose we have an array,

int mamun[ ]={3,4,5,6};

Suppose the elements are located in memory as

Elements:               3        4           5           6

Memory location: 1000   1002      1004      1005

Here is program that prints out the memory location in which the elements of this array are stored.

main( )

{

   int mamun[ ]={3,4,5,6};

   int i=0,*p;

   p=mamun;   /*Because the array name is a base address of first elemnt of the array. We cam also write it p=mamunb[0]*/

     while (i<=4)

 {

    printf(" \n Address = %u",&mamun[i]);

    printf("\n Element = %d", *p);

    i++;

    p++;

 }

}

output:

address             elements

1000                  3

1002                  4

1004                  5

1006                  6

in this program, to begin with  we have collected the base address of the array(address of 0^th  element) in the variable p using the statement,

p=mamun; /*assigns address 1000to p*/.

When we are inside the loop for the first time p contains the address 1000,and the value at this address is 24.

These continue till the last element of the array has bee n printed.

A word of caution! D o not attempt the following operations on pointer ... they would never work out.

1. Addition of two pointers.

2. Multiplying a pointer with a number.

3. Dividing a pointer with a number. 

written by mamun