COMP102

1
COMP102 Programming Fundamentals I

• LA2B (Mon 5-7pm)
• LA2E (Fri 3-5pm)
• LA2F (Fri 5-7pm)
• TA Jackie Lo

2
Lecture Review

• Arrays
• A collection of data elements with the same type
• E.g.
• Collection of integers
• Integer array
• Collection of characters
• Character array
• Each data in the collection is called
• An element

3
Lecture Review

• Array Declaration
• Syntax
• lttypegt ltarrayNamegtltarray_sizegt
• E.g.
• int array10
• Array elements
• Are values of the type
• lttypegt
• E.g.
• All element stored in int array10 are integer

4
Lecture Review

• Size of the array
• Represent the number of elements in the array
• Indicated by ltarray_sizegt
• E.g.
• int array10
• Can use to store 10 integers
• ltarray_sizegt must be
• An int constant
• A constant expression
• Note
• An array can have multiple dimensions
• E.g.
• int array1020

5
Lecture Review

• E.g.
• // array of 10 integer
• // which is uninitialized
• int array10

6
Lecture Review

• Subscripting
• To access an individual element
• Must apply a subscript to the corresponding array
• A subscript
• Use bracketed expression
• E.g.
• arrayx
• The expression in the brackets
• Known as the index
• E.g.
• x stated in arrayx

7
Lecture Review

• Note
• First element of array
• Has index 0
• array0
• Second element of array
• Has index 1, and so on
• array1, array2, array3,
• Last element
• Has an index array_size 1
• arrayarray_size 1
• E.g.
• If an array is declared as int array10
• Last element is array9

8
Subscripting

• E.g.
• // array of 10 uninitialized ints
• int array10
• array3 1
• int x array3

9
Lecture Review

• Use for loop to access/process all the elements
  of an array
• E.g.

for (i0 iltarray_size i) // assign value to
an element of array arrayi x // assign
value of an element to a variable x
arrayi
10
Array Initialization

• Declaration only reserves memory for the elements
  in the array
• No values will be stored
• To initialize an array
• Assign value to each of the element
• E.g.

int array10 9, 8, 7, 6, 5, 4, 3, 2, 1, 0
11
SUMMARY

• By the end of this lab, you should be able to
• Declare and manipulate both
• 1-D arrays

12
Lab10

• Download the template from website