1. Structure

2. 2
Declaring Structures
§ Array와 structure의 차이점
– array
• Array의 모든 element는 같은 type이여야 한다.
• Index를 사용하여 각 element를 access한다.
– structure
• 다른 type의 element로 구성 될 수 있다.
• 각 element는 name을 갖는다.
• Name에 의해 각 element를 access한다.

3. 3
Declaring Structures
§ struct declaration
– Collection of members(/elements)
[Ex] struct student { /* 2 elements로 구성된 structure */
int std_id;
char name [20] ;
} ;
int std_id, char name[20]
2 member를 포함하는 student라 불리우는 struct type을 정의

4. 4
Declaring Structures
§ struct declaration
- struct tag: 정의 되는 structure를 지정하기 위한 name.
- 한 번 structure tag인 student가 정의되면, 이제 tag를 사용하
여 같은 structure type의 변수를 선언할 수 있다.
[Ex] struct student {
int std_id;
char name [20] ;
};
[Ex] struct student p1, p2 ; /* correct declaration */
student p1, p2; /* wrong declaration */
struct tag:
생략 가능하지만..

5. 5
Accessing a Member
§ struct member operator ‘.’
– Structure의 각 member를 access하기 위해 ‘.’를 사용한다.
[Ex] struct student {
int std_id;
char name[20];
} ;
struct student p ;
p.std_id = 1 ;
strcpy( p.name, “Monica” ) ;
1
Monica
p
std_id
name

6. 6
Accessing a Member
§ member operation
[Ex] struct student {
int std_id;
char name[20];
}
struct student p ;
scanf(“%s”, p.name);
p.std_id = 258; /* assignment */
p.std_id++; /* increment */

7. 7
Declaring Structures
§ Example
int main()
{
int std_id ;
char name[20] ;
scanf( “%d”, &std_id ) ;
scanf( “%s”, name ) ;
printf( “%d ”, std_id ) ;
scanf( “%sn”, name ) ;
return 0;
}
struct student {
int std_id;
char name [20] ;
} ;
int main()
{
struct student p ;
scanf( “%d”, &p.std_id ) ;
scanf( “%s”, p.name ) ;
printf( “%d ”, p.std_id ) ;
printf( “%sn”, p.name ) ;
return 0;
}

8. 8
Declaring Structures
§ Initializing Struct variables
[Ex] struct student {
int std_id;
char name [20] ;
} ;
struct student person1 = { 1, “Gil Dong” } ;
struct student person2 = { 2, “Sun Shin” } ;
person1
person1.number person1.name
1 Gil Dong person2
person2.number person2.name
2 Sun Shin

9. 9
Structure Pointer
§ Pointer 선언
[Ex] struct student {
int std_id;
char name[20];
} ;
struct student s={1, “Gil Dong”}, *p ;
p = &s ;
s
1 Gil Dong
p

10. 10
Structure Pointer
§ Pointer를 통한 member access
[Ex] struct student {
int std_id;
char name[20];
} ;
struct student s, *p = &s ;
(*p).std_id = 10 ;
strcpy( (*p).name, “Sun Shin” ) ;
struct student s, *p = &s ;
p->std_id = 10 ;
strcpy( p->name, “Sun Shin” ) ;

11. 11
Structure Pointer
[Ex] struct shape {
int x, y ;
char name[10] ;
};
struct shape s, *p = &s;
scanf (“%d %d %s”, &p->x , &p->y, p->name ) ;
p->x *= 2;
p->y %= 5;
printf (“%d %d %sn”, p->x , p->y, p->name ) ;

12. 12
Structure Pointer
[Ex] struct shape {
int x, y ;
char name[10] ;
};
struct shape s, *p = &s;
scanf (“%d %d %s”, &(*p).x , &(*p).y, (*p).name ) ;
(*p).x *= 2;
(*p).y %= 5;
printf (“%d %d %sn”, (*p).x , (*p). y, (*p). name ) ;

13. 13
Precedence and Associativity of Operators
( ) [ ] . -> ++(postfix) --(postfix) left to right
++(prefix) --(prefix) ! ~ sizeof(type)
+(unary) -(unary) &(address) *(dereference)
right to left
* / % left to right
+ - left to right
<< >> left to right
< <= > >= left to right
== != left to right
& left to right
^ left to right
| left to right
&& left to right
|| left to right
? : right to left
= += -= *= /= %= >>= <<= &= ^= |= right to left

14. 14
Functions and Assignment
§ struct 변수에 값 넣기
struct student {
int std_id;
char name[20];
} p1, p2;
struct student p1 = { 1, “Gil Dong”}, p2 ;
p2 = p1 ; // OK???
1
Gil Dong
p1
?
?
p2
OK. 원하는 대로 잘 됨

15. 15
Functions and Assignment
§ struct 변수에 값 넣기
struct student {
int std_id;
char name[20];
} ;
int main() {
struct student p1 = { 1, “Gil Dong”}, p2 ;
copy_student( p1, p2 ) ;
return 0;
}
void copy_student( struct student p1,
struct student p2 )
{
p1.std_id = p2.std_id ;
strcpy( p1.name, p2.name ) ;
}
p2의 값은 어떻게 될까?

16. 16
Functions and Assignment
§ struct 변수에 값 넣기
void copy_student( struct student *p1,
struct student *p2 )
{
p1->std_id = p2->std_id ;
strcpy( p1->name, p2->name ) ;
}
struct student {
int std_id;
char name[20];
} ;
int main() {
struct student p1 = { 1, “Gil Dong”}, p2 ;
copy_student( &p1, &p2 ) ;
return 0;
}
p2의 값은 어떻게 될까?

17. 17
Arrays of Structure
§ Definition
[Ex] struct student {
int std_id;
char name[20];
} ;
struct student my_student[100] ;
my_student[0]
1 Gil Dong
my_student[1]
5 Sun Shin ………

18. 18
Initialization of Structures
§ Initializing an Array of Structures
[Ex] struct student {
int std_id ;
char name[20] ;
} ;
struct student my_student[20] =
{ {1, “Gil Dong”},
{2, “Sun Sin”},
{3, “Kuk Jung”},
:
} ;