The document discusses arrays in C programming. It defines an array as a group of related data items that share a common name, with each item indicated by an index number. One-dimensional arrays can be represented with a single subscript, while multi-dimensional arrays use multiple subscripts to reference elements by row and column. The document also covers declaring, initializing, and accessing arrays, including examples of one-dimensional, two-dimensional, and multi-dimensional arrays in C.

1. Array
Topics
 Array
 Dimension of Array
 Array initialization
 Multidimensional array

2. Array
 Array: An array is a group of related data
items that share a common name. A
particular value is indicated by writing a
number called index number or subscript in
brackets after array name. For example:
info[100] represent 100th
information.
 While the complete set of values is referred
to as an array, the individual values are
called elements. Arrays can be of any data
type.

3. One Dimensional Array
 A list of items can be given one variable
name using only one subscript and such a
variable is called a one dimensional array.
 In C, one dimensional can be represented
as: x[1], x[2], …….x[n]
 The subscript can begin with number 0. That
is x[0] is allowed.
 Declaration of Array:
data_type var_name[size];

4. Continue..
 Ex: int x[10]; declares x as a one
dimensional array which can contain
maximum 10 integer numbers. The
subscript can from 0 to 9.
 C language treats character strings simply
as arrays of characters.
 Ex: char name[10]; declares the name as a
character array (string) variable that can
hold a maximum of 10 characters.

5. Continue…
 Initialization of Arrays: Like the ordinary variable
we can initialize the elements of arrays at the time
of declaration.
 General form:
static type var_name[size]={list of values};
 The values in the list are separated by commas.
Ex: static int x[5]={1,5,6,10,7};
 If the number of values in the list is less than the
number of elements, then only that many elements
will be initialized. The remaining elements will be
set to zero automatically.
 Ex: static int x[5]={10, 5, 15}; will initialize the first
three elements to 10, 5, 15 and the remaining two
elements to zero.

6. Continue..
 The size may be omitted.
 Ex: static int x[ ] ={1,2,3,4};
 Character arrays may be initialized in a
similar manner. Thus the statement:
static char name[ ]= {‘T’,’O’,’M’};

7. Two dimensional Array
 C allows us to define tables (which has row
and column) of items by using two
dimensional array. General form:
type array_name[row_size][col_size];
 Ex: int num[10][5]; declares a variable num
of 10 rows and 5 columns that is 50 values
can be stored in the array. Each value can
be accessed by using two subscripts (row
number and column number).
 So num[4][2] mean the 3rd element in the 5th
row of the array num.

8. Initializing two dimensional Array
 Two-dimensional arrays may be initialized
by following their declaration with a list of
initial values enclosed in braces.
 Ex: static int table[3][2]={0,0,1,1,2,2};
initialize the elements to the first row to 0, 2nd
row to 1 and 3rd
row to 2.
 The initialization is done row by row.
Ex: static int table[3][2]={{0,0},{1,1},{2,2}};
 When all the elements are to be initialized to
zero, we can write:
static int table[3][5]={{0},{0},{0}};

9. Multidimensional Array
 C allows arrays of three or more
dimensions. The general form is:
type array_name[s1][s2]……[sn]; where si is
the size of the ith dimension.
 Ex: int x[5][4][6];
float y[5][5][4][3];

10. Program for average of N numbers
#define N 10
main()
{
int k, x[10], total=0;
float avg;
for(k=0;k<N;k++)
scanf(“%d”,&x[k]);
for(k=0;k<N;k++)
total = total+x[k];
avg=(float)total/N;
printf(“Average = %f”, avg);
}