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CS 112 Introduction to
Programming
Lecture #20:
Arrays
http://flint.cs.yale.edu/cs112/
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Outline
rAdmin. and review
rArrays
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Review: Defining and Using Classes
rUsing class to generate objects
mDeclare a variable as a type of a class
mCreate an object
mAssociate the object with a variable,
the variable is a reference to the object
e.g., Coin coin1;
coin1 = new Coin();
Coin coin2 = coin1;
rDefining class according to encapsulation
rSome other details
mobject life cycle
mstatic members
mreadonly and this
coin1
coin2
object
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Outline
rAdmin. and review
ØArrays
ØDeclaration, instantiation and initialization of
arrays
mExamples
•command line
•strings as arrays
•using array elements as counters
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Arrays
rAn array stores multiple elements of the same type
mthat type can be simple (value) types or objects
•for arrays of simple types, each element contains one value of
the declared type
•for arrays of reference types (e.g., objects), every element of
the array is a reference to an object of the data type of the
array
rRefer to particular element in the array by position
number
mthe name of the array followed by the position number
(subscript) of the element in square brackets ([])
•[ ] is considered as an operator
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Arrays: Declaration and Instantiation
rAn array can be allocated using the keyword new to specify how many elements
the array should hold
bool[] flags; // declare flags
flags = new bool[20]; // create an array and make flags a ref.
// now flags is reference to another array
flags = new bool[10];
// declare variable grades; create an array; make grades a
// reference of the array
int[] grades = new int[12];
float[] prices = new float[500];
string[] codes = new string[26];
Time1[] times;
times = new Time1[10];
