What is an array?
·
Arrays a kind of data structure that can
store a fixed-size sequential collection of elements of the same type.
·
An array is used to store a collection
of data, but it is often more useful to think of an array as a collection of
variables of the same type.
·
Instead of declaring individual
variables, such as number0, number1, ..., and number99, one array variable may
be declared such as numbers and use numbers[0], numbers[1], and ..., numbers[99]
to represent individual variables.
·
A specific element in an array is
accessed by an index.
Declaring
Arrays
·
To declare an array in C, a
programmer specifies the type of the elements and the number of elements
required by an array as follows −
type
arrayName [ arraySize ];
·
This is called a single-dimensional
array.
·
The arraySize must be an
integer constant greater than zero and type can be any valid C data
type.
·
For example, to declare a 10-element
array called balance of type double, use this statement −
double
balance[10];
·
Here balance is a variable
array which is sufficient to hold up to 10 double numbers.
Initializing
Arrays
·
An Array can be initialized in C
either one by one or using a single statement as follows −
double
balance[5] = {1000.0, 2.0, 3.4, 7.0, 50.0};
·
The number of values between braces
{ } cannot be larger than the number of elements that we declare for the array
between square brackets [ ].
·
If you omit the size of the array,
an array just big enough to hold the initialization is created. Therefore, if
you write −
double
balance[] = {1000.0, 2.0, 3.4, 7.0, 50.0};
·
You will create exactly the same
array as you did in the previous example. Following is an example to assign a
single element of the array −
balance[4]
= 50.0;
·
The above statement assigns the 5th
element in the array with a value of 50.0. All arrays have 0 as the index of
their first element which is also called the base index and the last index of
an array will be total size of the array minus 1. Shown below is the pictorial
representation of the array we discussed above –
·
Example to show an array with index
·
Example to show declaration and initialization
Output 1 2 3 4 5 6 7 8 9 10
Element[0] = 1
Element[1] = 2
Element[2] = 3
Element[3] = 4
Element[4] = 5
Element[5] = 6
Element[6] = 7
Element[7] = 8
Element[8] = 9
Element[9] = 10
WAP
to read and write an array.
#include
<stdio.h>
void
main ()
{ int n[ 10 ]; /* n is an array of 10 integers
*/
int i,j;
/* read an array */
for ( i = 0; i < 10; i++ )
scanf("%d" , &n[i]);
/* output each array element's value */
for (j = 0; j < 10; j++ )
printf("Element[%d] = %d\n", j,
n[j] );
}