One Dimensional Array in Data Structure

One Dimensional Array

If single subscript is required to reference an element of an array then it is known
as one dimensional array. One dimensional array is a homogeneous collection
of finite data elements which are referenced by an index number. One
dimensional arrays are also known as linear array.
An array ‘Age’ having 10 elements is shown below:

one dimensional array

Find length

Length = UB – LB + 1
UB is the upper bound or upper index of the array
LB is the lower bound or lower index of the array

Calculate Size of array

Bytes = length * size_of(data_type)
Data type specifies the type of elements stored in array
Size_of(data_type) depends upon the programming language. In case of ‘C’
language 2
bytes are required for integer type and 4 bytes are required for float type

Declaring One Dimensional Array

There are four components of a statement that declares an array.

  • Data type
  • An array name
  • The total number of array element to create
  • And a semicolon (;).
  • The semicolon tells the computer that the preceding is a statement. Declaring
    the array name, type of an array (data type) and setting the number of elements
    in the array is known as dimensioning the array. The array must be declared
    before its uses it in C/C++ program
    like other variables.

    There are two techniques for declaring an array
  • Can declare and initialize an array either where memory is reserved
    at compile time.
  • Where memory is dynamically reserved at runtime.
  • Declare an array either where memory is reserved at
    compile time

    This technique is similar in Java, C, and C++, except in Java you must initialize
    the array when the array is declared


    data_type array_name[array_size];

    data_type is used to declare the nature of the data elements stored in the array
    like character type, integer and float type. The data type is a keyword that tells
    the computer the amount of memory to reserve for each element of the array.
    If we use int data type for array then it told the computer to reserve enough
    memory to store an integer for each array.
    array_name is the name of the declared array. The array name is the name you
    use within a program to reference an array element.
    array_size is a positive integers which indicate the size of the array (how many
    locations are needed).

    Here’s valid declaration statement in C and C++:

    int student[20];
    float age[70];
    char class[12];