One-dimensional arrays and indexing

Overview

Index in an array, why an array is described as a random access structure and traversing an array.

What you need to know

Answer each one before you reveal it.

Questions from this subtopic

Each one with the model answer underneath.

1. 1

   What is an array?

   Model answer

   An array is an ordered set of data items of the same data type stored under one identifier. Each item is reached by its index.

2. 2

   Why must every element of an array share the same data type?

   Model answer

   A shared data type gives every element the same size in memory. The address of an element can then be calculated from its index.

3. 3

   What is an index in an array?

   Model answer

   An index is the position number that identifies one element of an array. The index is written in brackets after the identifier.

4. 4

   State the number of elements in an array declared with indices 0 to 9.

   Model answer

   The array holds ten elements. Index 0 counts as the first of them.

5. 5

   What does it mean to say an array is static?

   Model answer

   A static array has its size fixed when the program is written. The number of elements cannot change while the program runs.

6. 6

   Give one advantage of using an array rather than a set of separate variables.

   Model answer

   An array lets a loop process every value with one line of code. One identifier replaces many separate variable names.

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