Arrays (CIE IGCSE Computer Science)

A one-dimensional (1D) array is a collection of items of the same data type.

• To declare an array in pseudocode, use the syntax:
  DECLARE arrayName[n] OF dataType
• To declare an array in Python, use the syntax:
  array_name = [0] * n
• In Java, use the syntax:
  dataType[] arrayName = new dataType[n];
• In Visual Basic, use the syntax:
  Dim arrayName(n) As dataType

To access elements in a 1D array, use the index, which can start at 0 or 1.

A two-dimensional (2D) array is an array of arrays, creating a grid-like structure.

• To declare a 2D array in pseudocode using the syntax:
  DECLARE arrayName[n][m] OF dataType
• In Python, use the syntax:
  array_name = [[0] * m for _ in range(n)]
• In Java, use the syntax:
  dataType[][] arrayName = new dataType[n][m];
• In Visual Basic, use the syntax:
  Dim arrayName(n, m) As dataType

To access elements in a 2D array, use two indices: the row index and the column index.

The syntax for accessing elements is similar across languages, using square brackets:

• [i] for 1D arrays,
• and [i][j] for 2D arrays.