Tin h c c s 3ọ ơ ở
Structure
Outline
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Structured Data types
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Structures as function arguments
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Self-referential types: linked list
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Structure
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2
nd
aggregate data type: struct
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Recall: aggregate meaning "grouping"
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Recall array: collection of values of same type
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Structure: collection of values of different types
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Treated as a single item, like arrays
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Major difference: Must first "define"
struct
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Prior to declaring any variables
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Structure
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Sometimes referred as records.
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Structured Data Types
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Define struct globally (typically)
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No memory is allocated
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Just a “placeholder” for what struct will “look like”
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To define struct, we must give:
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Name of struct
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Name of each field
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Type of each field (could be another
record/struct)
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Defining Struct
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Defining a new data type using struct
struct date  name of new "type"
{
int day;  member names
int month;
int year;
};  “;” after “}”
struct date yesterday;
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today.year
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Called "member variables"
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The "parts" of the structure variable
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Different structs can have same name member
variables
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No conflicts
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Defining New Type Struct
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Could use typedef to define a new type
struct
typedef struct date Date;
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And then we could use Date as other
basic type without the need of
including struct
Date today;
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Compare to previous declaration of
yesterday
struct date yesterday;
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Structure Example
void printData(Date today)
{
printf("The day is: %i", today.day);

Simple assignments are legal:
apples = oranges;
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Simply copies each member variable from apples
into member variables from oranges
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Structure Other Operations
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Operations which are NOT defined for struct
type:
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compare for equality/inequality
(i.e. apples == oranges is not a legal expression)
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compare based on ordering (<, >, )
(i.e. apples < oranges is not a legal expression)
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arithmetic operations
(i.e. apples + oranges is not a legal expression)
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reading from or writing to text files
(i.e. no printf(apples) no scanf(&oranges))
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If you need such operations, write your own
functions.
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Structure and Pointer
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As for other types:
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Structure and Pointer
void getData(Date *today)
{
printf("Enter day: ");
scanf("%i", &((*today).day));
printf("Enter month: ");
scanf("%i", &(today->month));
printf("Enter year: ");
scanf("%i", &today->year);
}
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Structure as Function Argument
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Passed like any simple data type
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Pass-by-value
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Pass-by-reference
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Or combination
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Can also be returned by function
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Return-type is structure type
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Return statement in function definition
sends structure variable back to caller
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Other Type Definition

A very powerful programming technique
is to create struct with fields which
contain a reference to an object in
the same struct. For example:
struct list_node {
int data;
struct list_node *next;
};
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This approach can be used to create
some very useful data structures.
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Linked Lists
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Consider the following data
structure:
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A list that grow over time
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Items are added one by one
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Each item is a number
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It might grow like this:
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Linked Lists
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How do you implement such a list in C++?
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You can use an array but you must check the

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Linked Lists
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