1. Structure Problem Solving & Program Design in C Eighth Edition
Jeri R. Hanly & Elliot B. Koffman
© 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.

2. Name
Addr
Content
Lecture
Lecture++;

3. Structure Basics
A structure is a collection of data values, called data members, that form a single unit.
Unlike arrays, the data members can be of different types.

4. Structure Definition struct name { variable declaration; . };
the keyword struct announces that this is a structure definition

5. Struct Basics Definition of a structure: Example: The “Date” structure
struct <struct-type>{
<type> <identifier_list>;
...
} ;
Example:
struct Date {
int day;
int month;
int year;
Each identifier defines a member of the structure.
The “Date” structure
has 3 members,
day, month & year.

6. Struct Examples Example: The “StudentGrade” structure has 5 members of
struct StudentInfo{
int Id;
int age;
char Gender;
double CGA; };
struct StudentGrade{
char Name[15];
char Course[9];
int Lab[5];
int Homework[3];
int Exam[2];
The “StudentInfo” structure has 4 members
of different types.
The “StudentGrade” structure has 5 members of
different array types.

7. Struct Examples Example: The “StudentRecord” structure has 4
struct BankAccount{
char Name[15];
int AcountNo[10];
double balance;
Date Birthday; };
struct StudentRecord{
int Id;
char Dept[5];
char Gender;
The “BankAcount” structure has simple, array and structure
types as members.
The “StudentRecord” structure has 4
members.

8. Initializing Structures
struct Rect {
double x;
double y;
char color;
double width;
double height; };
struct Rect r1 = {0,0,’r’,5,10}; x y r
color
5.0
width
10.0
height

9. Accessing Data Members
To access a data member use
Varname.membername
struct Rect r1 = {0,0,’r’,5,10};
r1.x
r1.y
r1.color
r1.width
r1.height x y r
color 5
width 10
height

10. Assignment Operator
Assignment operator is defined for structure of the same type.
struct rect {
double x;
double y;
char color;
double width;
double height; };
struct rect r1, r2
r1.x = 10.5;
r1.y = 18.99;
r1.width = 24.2;
r1.height = 15.9;
r1.color = 'r';
/* Copy all data from r1 to r2. */
r2 = r1;

11. Nested Structures We can nest structures inside structures. Examples:
struct point{ double x, y; }; point P; struct line{ point p1, p2; }; line L; struct triangle{ point p1, p2, p3; }; triangle T;
(P.x, P.y)
(L.p2.x, L.p2.y)
(L.p1.x, L.p1.y)
(T.p2.x, T.p2.y)
(T.p3.x, T.p3.y)
(T.p1.x, T.p1.y)

12. Nested Structures point P; line L; triangle T; L.p1.x = 2; T.p1.x = 2;
P.y = 11;
(4, 11)
(10, 9)
L.p1.x = 2;
L.p1.y = 7;
L.p2.x = 10;
L.p2.y = 9;
(2, 7)
(6, 5)
T.p1.x = 2;
T.p1.y = 0;
T.p2.x = 6;
T.p2.y = 5;
T.p3.x = 8;
T.p3.y = 3;
(8, 3)
(2, 0)

13. Nested Structs struct address { char city[21]; char state[3];
char zip[6]; };
city
state
zip
struct address default;
strcpy(default.city, “Hammond”);

14. Nested Structs Given: struct address { char city[21]; char state[3];
char zip[6]; };
struct family_rec {
int id_num;
char name[15];
struct address addr;
double income;
} family1, family2;

15. Nested Structs family1 id_num name addr city (struct address) state
zip
income

16. Nested Structs - Accessing Members
family1.id_num = 5;
strcpy(family1.name,”Jones”);
strcpy(family1.addr.city,”Gary”);
strcpy(family1.addr.state,”IN”);
strcpy(family1.addr.zip,”46403”);
family1.income = ;

17. } HIRE_DATE, TERM_DATE, CURRENT_DATE; struct pay_period {
struct employee {
char name[MAXNAME];
int age;
} emp;
struct date {
int month, day, year;
} HIRE_DATE, TERM_DATE, CURRENT_DATE;
struct pay_period {
struct date start;
struct date end;
} Emp_Worked, Emp_Schedule;
struct employee_days_worked {
struct employee person
struct pay_period work_schedule;
} EMPLOYEE;
strcpy(EMPLOYEE.person.name,“Sherlock Holmes”);
EMPLOYEE.person.age = 27;
EMPLOYEE.work_schedule.start.month = 4;
EMPLOYEE.work_schedule.start.day = 5;
EMPLOYEE.work_schedule.start.year = 95;

18. Arrays of structures An ordinary array: One type of data
An array of structs: Multiple types of data in each array element. … …

19. Arrays of Structures We often use arrays of structures.
Example: StudentRecord Class[100]; strcpy(Class[98].Name, "Chan Tai Man"); Class[98].Id = 12345; strcpy(Class[98].Dept, "COMP"); Class[98].gender = 'M'; Class[0] = Class[98];
Chan Tai Man M
COMP
. . . …

20. Arrays Inside Structures
We can use arrays inside structures.
Example: struct square{ point vertex[4]; }; square Sq;
Assign values to Sq using the given square
(4, 3)
(10, 3)
(4, 1)
(10, 1)
x y
x y
x y
x y

21. Arrays of Structures ……….......
Arrays of structures may be declared in the same way as other C data types.
struct rect rectangles[20];
rectangles[0] references first structure of rectangles array.
rectangles[0].color = ‘r’; x y
………
color
width
height 1 2 3 19

22. Structures as Arguments to Functions
When a structure is passed as an argument to a function, it is a call-by-value reference.
Changes made to the formal parameters do not change the argument.
A pointer to a structure may also be passed as an argument to a function.
Changes made to the formal parameters also change the argument.

23. Call by Value Example s s1 Updated s struct simple { int ival;
double dval; };
struct simple fun1(struct simple s)
struct simple temp1;
temp1.ival = s.ival+1;
temp1.dval = s.dval + 2;
return temp1; }
int main(void)
struct simple temp2, s1 = {10, 1.5};
temp2=fun1(s1);
printf(“%i %lf\n”, temp2.ival , temp2.dval );
return 0; s s1 10 10
ival
1.5
1.5
dval
Updated s 11
3.5

24. Exercise (a,b)+(c,d)=(a+c,b+d) (a,b)*(c,d)=(a*c,b*d)
Write a program using structures that manipulates pairs. Addition and multiplication of pairs is defined below.
(a,b)+(c,d)=(a+c,b+d)
(a,b)*(c,d)=(a*c,b*d)

25. Pair Structure
Store two integers to represent the first and second number of pair
struct pair {
int first;
int second; };

26. Addition struct pair add(struct pair p1, struct pair p2) {
struct pair temp;
temp.first = p1.first + p2.first;
temp.second = p1.second + p2.second;
return temp; }

27. Multiplication struct pair multiply(struct pair p1, struct pair p2) {
struct pair temp;
temp.first = p1.first * p2.first;
temp.second = p1.second * p2.second;
return temp; }

28. How to use the functions
struct pair mp1,mp2,mp3,mp4;
printf("Enter first pair\n");
scanf("%d %d",&mp1.first, &mp1.second);
printf("Enter second pair\n");
scanf("%d %d",&mp2.first, &mp2.second);
mp3 = add(mp1, mp2);
printf("Addition result = (%d,%d)\n",mp3.first,mp3.second);
mp4 = multiply(mp1,mp2);
printf("Multiplication result = (%d,%d)\n",mp4.first,mp4.second);

29. Exercise Update the program to support the following on pairs
c*(a,b) = (c*a,c*b)
(a,b)^c = (a^c,b^c)

30. Nested Structures
Structure definitions may contain data members that are other structures:
struct Card {
char suit;
int rank; };
struct Deck
struct Card cards[52];
int next_card = 0;
Card
suit
rank 1 51
…...
cards ……
next_card

31. Initialize the Deck for (i=0; i<13; i++) for (i=26; i<39; i++) {
d1.cards[i].suit = 'h';
d1.cards[i].rank = (i-26)+1; }
for (i=39; i<52; i++)
d1.cards[i].suit = 's';
d1.cards[i].rank = (i-39)+1;
for (i=0; i<13; i++) {
d1.cards[i].suit = 'c';
d1.cards[i].rank = i+1; }
for (i=13; i<26; i++)
d1.cards[i].suit = 'd';
d1.cards[i].rank = (i-13)+1;

32. Print the Deck void print(struct Deck d1) { int i;
for (i=0; i<52; i++)
printf("%c %d\n", d1.cards[i].suit, d1.cards[i].rank);
return; }

33. How to Shuffle the Deck? for (i=0; i<52; i++) {1 2 3 51
…………………………
for (i=0; i<52; i++) {
// pick a random card x from 0-51
// swap card x and card i }

34. BlackJack Shuffle the deck Deal first 2 cars to user
Print both cards on screen
Next two cards to dealer
Print only the first on screen
Ask user whether he/she wants to continue
Highest total <= 21 wins
Jack, Queen, King are 10 points
Ace is 11 points
Other cards represented by their number