Arrays and pointers, Data Structure & Algorithms

Assignment Help:

C compiler does not verify the bounds of arrays. It is your job to do the essential work for checking boundaries wherever required.

One of the most common arrays is a string that is simply an array of characters finished by a null character. The value of any null character is o. A string constant is a one-dimensional array of characters terminated by a null character (\0).

For instance, consider the following:

char message[ ]= {'e', 'x', 'a', 'm', 'p', 'l','e','\0'};

Also, assume the following string that is stored in an array:

"sentence\n"

Given figure illustrates the way a character array is stored in memory. In the array each of character occupies one byte of memory and the last character is always '\0'. Note down that '\0' and '0' are not the same. The character array elements are stored up in contiguous memory locations.

s

e

n

t

e

n

c

e

\n

\0

                                          Figure: String in Memory

C concedes a fact that the user would employ strings very frequently and therefore provides a short cut for initialization of strings.

For instance, the string used above can also be initialized as char name[ ] = "sentence\n";

Note down that, in this declaration '\0' is not essential. C automatically inserts the null character.

Multidimensional arrays are described in the similar manner as one-dimensional arrays, apart from that a separate pair of square brackets is needed for each of subscript. Therefore a two-dimensional array will need two pairs of square brackets, a three-dimensional array will need three pairs of square brackets and so on.

In C the format of declaration of multidimensional array is given below:

data_type array_name [expr 1] [expr 2] .... [expr n];

where data_type is the type of array like char, int etc., array_name is the name of array & expr 1, expr 2, ....expr n are positive valued integer expressions.

The diagram of two-dimensional array of size 3 × 5 is illustrated in Figure

 

2052_ARRAYS AND POINTERS.png

Figure: Schematic of a Two-Dimensional Array

In the particular case of a two-dimensional array, the given formula yields the number of bytes of memory required to hold it:

bytes = size of 1st index × size of 2nd index × size of (base type)

The pointers & arrays are closely associated. As you know, an array name without an index is a pointer to the primary element in the array.

Assume the following array:

char p[10];

p and &p[0] are similar because the address of the primary element of an array is the similar as the address of the array. Thus, an array name without an index produced a pointer. On the other hand a pointer can be indexed as if it were declared to be an array.

For instance, assume the following program fragment:

int *x, a [10];

x = a;

x[5] = 100;

* (x+5) = 100;

Both of the assignment statements place the 100 in the sixth element of a. In addition the (0,4) element of a two-dimensional array might be referenced in the given two ways: either through array indexing a[0][4], or through the pointer *((int *) a+4).

Generally, for any two-dimensional array a[j][k] is equivalent to:

*((base type *)a + (j * rowlength)*k)


Related Discussions:- Arrays and pointers

Encryption the plain-text using the round keys, Encryption the plain-text u...

Encryption the plain-text using the round keys: 1. (Key schedule) Implement an algorithm that will take a 128 bit key and generate the round keys for the AES encryption/decryp

Hasing and indexing, differentiate between indexing and hashing in file org...

differentiate between indexing and hashing in file organization

Undirected graph, Graphs are data structures which consist of a set of vert...

Graphs are data structures which consist of a set of vertices & a set of edges which connect the vertices. A graph where the edges are directed is called directed graph. Or else, i

What is ruby, What is Ruby Ruby has numerous simple types, including nu...

What is Ruby Ruby has numerous simple types, including numeric classes such as Integer, Fixnum, Bignum, Float, Big Decimal, Rational, and Complex, textual classes like String,

Define the term counting - pseudocode, Define the term counting - Pseudocod...

Define the term counting - Pseudocode Counting in 1s is quite simple; use of statement count = count + 1 would enable counting to be done (for example in controlling a repeat

Preorder - postorder and inorder, 1) preorder, postorder and inorder 2) ...

1) preorder, postorder and inorder 2) The main feature of a Binary Search Tree is that all of the elements whose values is less than the root reside into the nodes of left subtr

Algorithm that inputs the codes for all items in stock, A shop sells books,...

A shop sells books, magazines and maps. Every item is identified by a unique 4 - digit code. All books have a code which starts with 1, all maps have a code starting with 2 and all

Which data structure is used for implementing recursion, Which data structu...

Which data structure is used for implementing recursion Stack.

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd