Array

Array is collection of homogenious data stored under unique name. The values in an array is called as 'elements of an array'. These elements are accessed by numners called as 'Subscripts or index numbers.' Arrays may be of any variable type.

Array is also called as 'Subscripted variable.'

Types of an Array:

One / Single Dimensional Array
Two Domensional Array

Sinple / One Dimensional Array

The array which is used to represent and store data in a linear form is called as 'Single or One Dimensional Array.'

Syntax:

  < data_type > < array_name >[size];

Examples:

int a[3] = { 2, 3, 5 }

char ch[20] = "TechnoExam";

float stax[3] = { 5003.23, 1940.32, 123.20 }

Total Size (in Bytes):

total size = length of array * size of data type

-----------------

In above example, a is an array of type integer which has storage size of 3 elements. The total size would be 3 * 2 = 6 bytes

* Memory Allocation:

  

    #include< studio.h >
    #include< conio.h >
    void main()
    {
      int a[3], i;
      clrscr();
        printf("\n\t Enter three numbers:");
        for(i=0; i<3; i++)
        {
          scanf("%d", &a[i]);   // read array
        }
        printf("\n\n\t Numbers are :");
        for(i=0; i<3; i++)
        {
          printf("\t %d", a[i]);  // print array
        }
        getch();
    }

    Output:
    Enter three numbers: 9 4 6
    Numbers are: 9    4    6

Features:

Array size shoud be positive number only
String array always terminate with null character ('\0')
Array element are countered from 0 to n-1
Useful for multile reading of elements (numbers)

Disadvantages:

There is no easy method to initialize large number of array elements
It is difficult to initialize selected elements.

Two Dimensional Array

The array which is used to represent and store data in a tabular form is called as TWO DIMENSIONAL ARRAY. such type of array specially used to representn data in a matrix form.

The following syntax is used to represent two dimensional array.

  
    
Syntax:
    < data-type > < array_nm >[row_subscript][Column-subscript];

    Example
    int a[3][3];

In the above example, 'a' is an array of type integer which has storage size of 3 * 3 matrix. The total size wpuld be 3 * 3 * 2 18 bytes.

It is also called 'multidimensional array.'

* Memory Allocation:

Program

  
    #include< stdio.h >
    #include< conio.h >
    void main()
    {
      int a[3][3], i, j;
      clrscr();
      printf("\n\t Enter matrix of 3 * 3 : ");
      for(i=0; i<3; i++)
      {
        for(j=0; j<3; j++)
        {
          scanf("%d", &a[i][j]); // read 3 * 3 matrix
        }
      }
      printf("\n\tMatrix is : \n");
      for(i=0; i<3; i++)
      {
        for(j=0; j<3; j++)
        {
          printf("\t %d", a[i][j]); // print 3 * 3  array
        }
      }
      getch();
    }

    output:
      Enter matrix of 3 * 3 : 3 4 6 7 2 1 2 3
      Matrix is:
      3   4   5
      6   7   2
      1   2   3

Limitations of Two Dimensional Array

We cannot delete any element from an array
If we don't know that how many elements have to be stored in a memory is advance, then there will be memory wastage if large array size is specified.

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