3. linked list
TRANSCRIPT
Linear List - Linked List -
Geun-Hyung Kim UMCL @ Dong-Eui University
리스트�(List)�개념
리스트�/�선형리스트�순서가�있는�항목의�모임�
기본�연산:��추가(add),�제거(delete),�검색(search)�등�
리스트를�구현하는�대표적인�방법:�배열,�연결리스트�
배열�구현이�간단하고�효율적임�-�배열의�인덱스�번호로�저장공간�접근�가능�
리스트의�크기가�고정�-�저장공간�재�할당이�필요�
리스트의�중간에�항목을�추가/삭제�시�다른�항목을�옮겨야�함�
연결리스트�리스트의�중간에�항목을�추가/삭제�시�다른�항목을�옮길�필요�없음��
링크�필드를�위한�추가�저장�공간이�필요�
리스트의�중간�항목을�바로�접근하는�것이�불가능��
배열과�연결�리스트
Tuesday
Friday
Wednesday
Monday
예)�이번주�약속�목록
배열
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�
Tuesday
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Friday
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NULL
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연결�리스트�(head:101)
배열�리스트의�추가�제거
Tuesday
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WednesdayMonday
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Tuesday
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WednesdayMonday
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add�‘Saturday’��on�2nd�position
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delete�‘Friday’�
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WednesdayMonday
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Satursday
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연결�리스트의�추가�제거
Tuesday
Monday
Wednesday
Friday
100
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NULL
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연결�리스트�(head:101)
Tuesday
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NULL
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Tuesday
Monday
Wednesday
Saturday
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NULL
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add�‘Saturday’�on�2nd�position
delete�‘Friday’
�노드�(node)
노드�(Node)
노드는�리스트를�연결�리스트로�구현할�때��리스트의�각�요소�(element)의�정보를�저장공간에�저장하는�단위�
각�노드는�실제�정보를�저장하는�데이터�필드와�다른�노드를�가리키는�링크�필드로�구성�
data
link
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data
link
Saturday
�
data
link
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data
link
Monday
NULL
head
연결리스트의�마지막�노드의�링크�필드는�NULL�값을�갖는다.
연결리스트의�첫�노드의�주소는�head�pointer에�별도로�저장하여야�한다.
연결리스트를�구성하는�노드의�링크�필드는�다음�노드의�주소를�가리킨다.
노드의�C�언어�구현
struct node { int data; struct node *link;}
데이터�필드�(정수�값�저장)
링크�필드��(sturct�node�자료형의��주소를�저장하는�변수)
노드�구조체�정의��(새로운�자료형�정의)
typedef struct node ListNode;ListNode *head;
struct�node��자료형을�ListNode�자료형으로�재�정의
head�포인터�변수�선언
동적�메모리�할당
typedef struct node { int data; struct node *link;} ListNode;
ListNode *p1;p1 = (ListNode *)malloc(sizeof(ListNode)):
구조체의�정의와�동시에��새로운�ListNode�자료형�정의
예제�프로그램
int main() { ListNode *head = (ListNode *)malloc(sizeof(ListNode)); head->data = 10; head->link = NULL;
ListNode *newNode = (ListNode *)malloc(sizeof(ListNode)); newNode->data = 20; newNode->link = NULL; head->link = newNode;
newNode = (ListNode *)malloc(sizeof(ListNode)); newNode->data = 30;newNode->link = NULL;
head = newNode;
ListNode *p = head; while(p!=NULL) {
printf(“%d\n”, p->data);p = p->link;
}}
NULL10head
int main() { ListNode *head = (ListNode *)malloc(sizeof(ListNode)); head->data = 10; head->link = NULL;
ListNode *newNode = (ListNode *)malloc(sizeof(ListNode)); newNode->data = 20; newNode->link = NULL; head->link = newNode;
newNode = (ListNode *)malloc(sizeof(ListNode)); newNode->data = 30;newNode->link = NULL;
head = newNode;
ListNode *p = head; while(p!=NULL) {
printf(“%d\n”, p->data);p = p->link;
}}
예제�프로그램
10head
NULL20newNode
int main() { ListNode *head = (ListNode *)malloc(sizeof(ListNode)); head->data = 10; head->link = NULL;
ListNode *newNode = (ListNode *)malloc(sizeof(ListNode)); newNode->data = 20; newNode->link = NULL; head->link = newNode;
newNode = (ListNode *)malloc(sizeof(ListNode)); newNode->data = 30;newNode->link = head;
head = newNode;
ListNode *p = head; while(p!=NULL) {
printf(“%d\n”, p->data);p = p->link;
}}
예제�프로그램
10head
NULL20newNode 30
int main() { ListNode *head = (ListNode *)malloc(sizeof(ListNode)); head->data = 10; head->link = NULL;
ListNode *newNode = (ListNode *)malloc(sizeof(ListNode)); newNode->data = 20; newNode->link = NULL; head->link = newNode;
newNode = (ListNode *)malloc(sizeof(ListNode)); newNode->data = 30;newNode->link = head;
head = newNode;
ListNode *p = head; while(p!=NULL) {
printf(“%d\n”, p->data);p = p->link;
}}
예제�프로그램
10
head
NULL20
p 30
30
1020
예제�프로그램
int main() { ListNode *head = (ListNode *)malloc(sizeof(ListNode)); head->data = 10; head->link = NULL;
ListNode *newNode = (ListNode *)malloc(sizeof(ListNode)); newNode->data = 20; newNode->link = NULL; head->link = newNode;
newNode = (ListNode *)malloc(sizeof(ListNode)); newNode->data = 30;newNode->link = NULL;
head = newNode;
ListNode *p = head; while(p != NULL) {
printf(“%d\n”, p->data);p = p->link;
}}
연결리스트�맨�앞에�노드�추가�하기
data
link
30
�
data
link
20
�
data
link
10
�
data
link
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NULL
head
(1)새로운�노드를�만들고�데이터를�저장한다.
data
link
40
�
(2)�새로운�노드의�link�필드가�현재의�head�노드를�가리키도록�한다.
(3)�새로운�노드를��새로운�head�노드로�한다.
연결리스트�맨�앞에�노드�추가�하기
data
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data
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newNode = (ListNode *)malloc(sizeof(ListNode));newNode->data = 40;
head = newNode;
newNode->link = head;
연결리스트�맨�앞에�노드�추가�하기
함수�정의(구현�1)�반환�자료�형:�없음�함수�이름:�insertFirst�입력�파러미터(1):�저장할�정수�값�
void insertFirst(int item){
ListNode *node = (ListNode *) malloc(sizeof(ListNode));node->data = item;node->link = head;head = node;
}
Q)�head는�어디에�있나�?
모든�함수에서�직접�접근이�가능하도록�전역�변수로�선언되어�있음��
함수호출�예:�insertFirst(10);
연결리스트�맨�앞에�노드�추가�하기
반환�자료�형:�없음�함수�이름:�insertFirst�입력�파러미터(2):�저장할�정수�값,�첫�노드의�가리키는�head�포인터�변수의�주소
void insertFirst(ListNode **ptrHead, int item){
ListNode *node = (ListNode *) malloc(sizeof(ListNode));node->data = item;node->link = *ptrHead;*ptrHead = node;
}
함수호출�예: insertFirst(&head, 10);
첫�노드를�가리키는�head�포인터가�로컬��변수로�선언되어�있음
Q)�head의�정보를�전달할�때�**ptrHead를��사용하는�이유는�?
head�포인터의�값을�insertFirst()�함수�내에서�변경되어야�하고�함수�밖에서도�변경이�반영되어야�하기�때문에�head�포인터의�주소를�전달해야�하므로��
함수�정의(구현�2)�
연결리스트�맨�앞에�노드�추가�하기
반환�자료�형:�ListNode�자료를�가리키는�주소�값�함수�이름:�insertFirst�입력�파러미터(2):�저장할�정수�값,�첫�노드의�가리키는�head의�값
ListNode *insertFirst(ListNode *head, int item){
ListNode *node = (ListNode *) malloc(sizeof(ListNode));node->data = item;node->link = head;return node;
}
함수호출�예: head = insertFirst(head, 10);
함수�정의(구현�3)�
특정�노드�뒤에�새로운�노드�추가�하기
data
link
30
�
data
link
20
�
data
link
10
�
data
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NULL
head
(1)새로운�노드를�만들고�데이터를�저장한다.
data
link
40
�
(2)�새로운�노드의�link�필드가��������현재의�head�노드를�가리키도록�한다.
(3)�새로운�노드를��prev의�다음�노드로�설정한다.
prev
특정�노드�뒤에�새로운�노드�추가�하기
data
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data
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data
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head
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newNode = (ListNode *)malloc(sizeof(ListNode));newNode->data = 40;
prev->link = newNode;
newNode->link = prev->link;
특정�노드�뒤에�새로운�노드�추가�하기
특정�노드�뒤에�새로운�노드�추가�하기특정�노드�뒤에�새로운�노드�추가�하기
반환�자료�형:�없음�함수�이름:�insertAfterNode�입력�파러미터(2):�저장할�정수�값,�데이터를�저장할�위치�전�노드의�주소�값
void insertAfterNode(ListNode *prev, int item){
ListNode *node = (ListNode *) malloc(sizeof(ListNode));node->data = item;node->link = prev->link;prev->link = node;
}
함수�정의(구현)�
두가지�노드�추가�기능��통합�
반환�자료�형:�없음�함수�이름:�insertNode�입력�파러미터(3):�head�포인터�변수의�저장�주소,�저장할�위치�앞의�노드�주소,����������������������������새로운�노드의�주소
함수�정의(구현)�
void insertNode(ListNode** phead, ListNode* p, ListNode* newNode){ if(*phead == NULL){ //공백�리스트�� newNode->link = NULL; *phead = newNode; } else if(p == head){ //p가�NULL로�리스트의�첫번째�노드에�삽입 newNode->link = *phead;
*phead = newNode; } else{ //p 다음에�삽입� newNode->link = p->link; p->link = newNode; }}
연결리스트의�첫번째�노드�삭제
data
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data
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headhead�가�두번�째�노드를�가리키도록�함�
head = head->link;
연결리스트의�첫번째�노드�삭제
반환�자료�형:�삭제한�노드의�주소�함수�이름:�removeFirst�입력�파러미터(0):�없음�(head가�전역변수�일때)
ListNode *removeFirst(){
if (head == NULL) return NULL;else { ListNode *node = head->link; head = head->link; return node;}
}
함수�정의(구현�1)�
연결리스트의�첫번째�노드�삭제
반환�자료�형:�삭제한�노드의�주소�함수�이름:�removeFirst�입력�파러미터(1):�head�포인터의�주소�(head�가�로컬�변수�일때)
ListNode *removeFirst(ListNode **head){
if (*head == NULL) return NULL;else { ListNode *node = *head->link; *head = *head->link; return node;}
}
함수�정의(구현�2)�
특정�노드�뒤의�노드를�삭제�하기
data
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�
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data
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headprev
prev�노드가��prev�노드가�가리키는�노드의��다음�노드를�가리키도록�한다�
반환�자료�형:�삭제한�노드의�주소�함수�이름:�removeAfter�입력�파러미터(2):�head�포인터�변수의�주소�(head�가�로컬�변수�일때),�데이터를�삭제할�노드의�전�노드�주소�값
함수�정의(구현)�
특정�노드�뒤의�노드를�삭제�하기
ListNode *removeAfter(ListNode **head, ListNode *prev){
ListNode *node = prev->link;if (*head == NULL) return NULL;else if (node == NULL) return NULL;
else { prev->link = node->link; return node;}
}
연결�리스트�순회하기
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data
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dat
lin
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head
p
연결리스트�순회는�리스트의�모든�노드를�처음부터�순차적으로�방문하는�것을�뜻한다.�
각�노드가�다음�노드의�데이터가�저장된�주소�정보를�가지고�있으므로�이를�이용하여��
모든�노드를�순회할�수�있다.
연결리스트�순회하기
반환�자료�형:�없음�함수�이름:�traverse�입력�파러미터(1):�head�포인터�변수에�저장된�값
ListNode traverse(ListNode *head){
ListNode *p = head;while (p != NULL) { p = p->link;}
}
함수�정의(구현)�
연결리스트에서�원하는�값�탐색
반환�자료�형:��ListNode�자료형의�주소�함수�이름:�search�입력�파러미터(2):�head�포인터에�저장된�값,�탐색하려는�정수�값
ListNode *search(ListNode *head, int value){
ListNode *p = head;while (p != NULL) { if (p->data == value) return p; p = p->link;}return p;
}
함수�정의(구현)�
두�연결�리스트의�연결�
반환�자료�형:��ListNode�자료형의�주소�함수�이름:�concat�입력�파러미터(2):�첫�번째�연결리스트와�두번째�연결리스트의�head�값�
ListNode *concat(ListNode *head1, ListNode *head2){
ListNode *p;if(head1 == NULL) return head2;else if (head2 == NULL) return head1;else {p = head1;
while (p->link != NULL) { p = p->link; } p->link = head2; return head1;}
}
함수�정의(구현)�
연결리스트를�역순으로�만들기
data
link
30
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qr알고리즘�고찰�1.�첫�노드의�link�값(r->link)�을�NULL�로�설정
NULL
2.�두번째�노드의�link�값(q->link)을�이전의�노드(r)로�설정
문제�발생:�다음�링크에�대한�정보가�없어짐��해결방안:�2의�link�값을�변경하기�전에�link�값�(p)�을�저장해�놓아야�함�
p
1-1.��두번째�노드(q)의�다음�노드를�저장�(p)�
3.�p,�q,�r을�모두�하나씩�오른쪽을�이동� r = q;q = p;p = p->link;q->link = r;
연결리스트를�역순으로�만들기
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p
p=head;q=Null;
q
q=p;p=p->link;
r=q;
1. 초기 상태
q->link=r;
NULL
r
NULL
r=q;q=p;p=p->link;
q->link=r;
r=q;q=p;p=p->link;
q->link=r;
r=q;q=p;p=p->link;
q->link=r;
�
연결리스트를�역순으로�만들기
반환�자료�형:��ListNode�자료형의�주소�함수�이름:�reverse�입력�파러미터(1):�head�포인터에�저장된�값
ListNode *reverse(ListNode *head){
ListNode *p, *q, *r;q=NULL;p=head;while (p!=NULL){ r=q; q=p; p=p->link; q->link=r;}return q;
}
함수�정의(구현)�
새로운�노드를��새롭게�생성하는�함수
반환�자료�형:�동적으로�생성한�노드의�주소��함수�이름:�createNode�입력�파러미터(2):��저장할�데이터,�노드에�연결할�다른�노드�주소�
ListNode *createNode(int data, ListNode *link){
ListNode *newNode = (ListNode *)malloc(sizeof(ListNode));if(newNode == NULL)error(“memory allocation error”);
newNode->data = data;newNode->link = link;return newNode;
}
함수�정의(구현)�
원형�연결�리스트�- Circular Linked List -
원형�연결�리스트�
data
link
30
�
data
link
20
�
data
link
10
�
data
link
100
�
head
원형�연결�리스트 마지막�노드가�첫�번째�노드를�가리키는�연결�리스트
data
link
30
�
data
link
20
�
data
link
10
�
data
link
100
�
head
원형�연결�리스트�처음에�노드�추가�
newNode->link = head->link;
head->link = newNode;
data
link
30
�
data
link
20
�
data
link
10
�
data
link
100
�
head
data
link
40
�
원형�연결�리스트�처음에�노드�추가�
반환�자료�형:�없음�함수�이름:�insertFirst2Circular�입력�파러미터(2):�head�포인터�변수의�주소,�새로운�노드�
void insertFirst2Circular(ListNode **phead, ListNode *newNode){
if (*phead == NULL){ // 공백 리스트 *phead = newNode; newNode->link = newNode;}else{ newNode->link = *phead->link; *phead->link = newNode;}
}
함수�정의(구현)�
원형�연결�리스트�마지막에�노드�추가
data
link
30
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data
link
20
�
data
link
10
�
data
link
100
�
head
data
link
40
�
newNode->link = head->link;
head->link = newNode;
head = newNode;
원형�연결�리스트�마지막에�노드�추가
반환�자료�형:�없음�함수�이름:�insertLast2Circular�입력�파러미터(2):�head�포인터�변수의�주소,�새로운�노드�
void insertLast2Circular(ListNode **phead, ListNode *newNode){
if (*phead == NULL){ // 공백 리스트 *phead = newNode; newNode->link = newNode;}else{ newNode->link = *phead->link; *phead->link = newNode; *phead = newNode;}
}
함수�정의(구현)�
원형�연결�리스트�순회하기
data
link
30
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data
link
20
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data
link
10
�
data
link
100
�
head
p
순회�종료�조건p->link == head
ListNode traverse(ListNode *head){
ListNode *p = head;while (p->link != head) { p = p->link;}
}
연결리스트�응용��-�다항식�-
연결�리스트�응용:�다항식�표현
다항식 p(n)=anxn+an-1xn-1+…+a0
연결리스트를�이용하여�하나의�다항식을�표현하는�구조체�(Polynomial)를�정의�
다항식을�항들의�연결�리스트로�표현�
항�들은�차수의�내림차순으로�정렬하여�저장하고�동일�차수의�항은�2개�이상�가지지�않으며�계수가�0인�항은�존재하지�않음��
하나의�항은�계수와�지수로�표현하며�하나의�항도�구조체(Term)로�표현�
다항식�표현�예
coef
link
3
12
�
expo
A(x)=3x12+4x8+1
coef
link
4
8
�
expo
coef
link
1
0
NULL
expo
Term Term Term
name
size
A
�
3
first
Polynomial
구조체�Term
typedef struct Term {int coef;int expo;struct Term *link;
}Term;
구조체�Polynomial
typedef struct Polynomial {char name[20];Term *first;int size;
} Polynomial;
새로운�항목�생성하기
Term *createTerm(int coef, int expo) {Term *term = (Term *)malloc(sizeof(Term));term->coef = coef;term->expo = expo;term->link = NULL;return term;
}
Polynomial *createPolynomial(char* name) {Polynomial *poly = (Polynomial *)malloc(sizeof(Polynomial));strcpy(poly->name, name); term->size = 0;term->first = NULL;return poly;
}
다항식에�항목�추가하기
coef
link
3
12
�
expo
coef
link
4
8
�
expo
coef
link
1
0
NULL
expo
Term Term Term
name
size
A
�
3
first
Polynomial
addTermtoPloy(int c, int e, Polynomial *p);
다항식�p에�차수가�e이고�계수가�c인�항을�더하기
알고리즘�개요�추가하려는�항의�차수가�다항식에�있으면,�coef�값에�계수�값을�더함�
추가하려는�항의�차수가�다항식에�없으면,�Term을�생성후�값을�대입하고�올바른�위치에�추가
다항식에�항목�추가하기
coef
link
3
12
�
expo
coef
link
4
8
�
expo
coef
link
1
0
NULL
expo
Term Term Term
name
size
A
�
3
first
Polynomial
새로운�항이�추가되는�경우�:�6x10�을�추가하는�경우�
coef
link
6
10
NULL
expo
Term *cur = p->first, *prev = null;
cur
while(cur != NULL && cur->expo > e){prev = cur;cur = cur->link;
}
prev
prev->link = newTerm;newTerm->link =cur;
�
void addTermtoPoly(int c, int e, Polynomial *p) {if (c ==0 || p == NULL) return;Term *cur = p->first, *prev =NULL;while (cur != NULL && cur->expo > e) {prev = cur;cur = cur->link;
}if (cur != NULL && cur->expo == e) {cur->coef += c;if(cur->coef == 0) { if (prev == NULL) p->first = cur->link; else prev->link = cur->link; p->size--; free(cur);}return;
}Term *newTerm = createTerm(c, e);if (prev == NULL) p->first = newTerm;else { prev->link = newTerm; newTerm->link = cur;}p->size++;
}
다항식에�항목�추가하기�-구현
다항식�출력하기
void polyPrint(Polynomial *poly) {Term *ptrTerm = poly->first;for (int i = 0; i < poly->size; i++) {
printf("%dx^%d ", ptrTerm->coef, ptrTerm->expo); if (i != poly->size -1) printf(" + "); ptrTerm = ptrTerm->link; } printf("\n");}
다항식�삭제하기
void delPolynomial(Polynomial *poly) {Term *ptrTerm = poly->first, *cur;for (int i = 0; i < poly->size; i++) {cur = ptrTerm;
ptrTerm = ptrTerm->link; free(cur); } free(poly);}
�두�다항식�더하기다항식�더하기
Polynomial *addPoly(Polynomial *a, Polynomial *b) {
Term *pa = a->first, *pb = b->first, *newTerm; int coef, expo; Polynomial *result = createPolynomial(“sum”);
while (pa != NULL && pb != NULL) { if (pa->expo > pb->expo) { coef = pa->coef; expo = pa->expo; addTermtoPoly(coef, expo, result); pa = pa->link; } else if (pa->expo == pb->expo) { coef = pa->coef + pb->coef; expo = pa->expo; addTermtoPoly(coef, expo, result); pa = pa->link; pb = pb->link; } else { coef = pb->coef; expo = pb->expo; addTermtoPoly(coef, expo, result); pb = pb->link; } } while (pa != NULL){addTermtoPoly(pa->coef, pa->expo, result); pa = pa->link;} while (pb != NULL){addTermtoPoly(pb->coef, pb->expo, result); pb = pb->link;}
return result;}
Summary of Linked Lists
#ifndef _Linked_List_#define _Linked_List_
ListNode *createNode(int data, ListNode *link);void insertFirst(ListNode **ptrHead, int item);void insertAfterNode(ListNode *prev, int item);void insertNode(ListNode** phead, ListNode* p, ListNode* newNode);ListNode *removeFirst(ListNode **head);ListNode *removeAfter(ListNode **head, ListNode *prev);ListNode traverse(ListNode *head);ListNode *search(ListNode *head, int value);ListNode *concat(ListNode *head1, ListNode *head2);ListNode *reverse(ListNode *head);
#endif
Linked_List
Linked_List:�추가되어야�할�요소
int isEmpty(ListNode *ptrHead); // List가�비어�있는지�확인�int getLength(ListNode *ptrHead); // List의 Node 수�확인�// List에서 pos에�있는 Node를�반환��ListNode *getNodeAt(ListNode *ptrHead, int pos);// List에서�pos에�있는 data를�반환��int getEntryAt(ListNode *ptrHead, int pos);// List에서�주어진�위치에�데이터�삽입�void insertNodeAt(ListNode **ptrHead, int pos, int item);// List의�마지막에�데이터�삽입�void insertLast(ListNode **ptrHead, int item);// List에서�주어진�위치의�데이터를�삭제ListNode *removeAt(ListNode **ptrHead, int pos);// List의�모든�노드를�삭제�void removeAll(ListNode *ptrHead);// List의�모든�노드의�데이터�출력�void printData(ListNode *ptrHead);
�연결�리스트�응용�- line editor -
Line�Editor Editor�Command�창에서�한�줄씩�입력하거나�삭제�
라인�번호와�라인의�내용을�입력받아�지정된�위치에�저장�
각�라인에�해당하는�텍스트를�연결�리스트�노드의�데이터로�처리�
커서를�사용하지�않는�단순한�에디터�
파일을�이용하여�문서를�저장�및�편집
Line�Editor
파일�읽고�쓰기�위한�기본�함수��파일을�열고�닫는�함수:�fopen,�fclose�
파일로�부터�데이터를�읽는�함수:�fscanf,�fgets,�fread��
파일로�데이터를�쓰는�함수:�fprintf,�fputs
Line Editor: fopen/fclose
fopen() 함수�프로토타입: FILE* fopen(const char* filename, const char* mode);
FILE: _iobuf라는�구조체�(입출력장치에�대한�관련�정보�저장)
filename: 읽거나�쓰고자�하는�파일�이름mode (파일�액세스�모드): r, w, a, r+, w+, a+, t , b
fclose() 함수�프로토타입:
int fclose(File* fprt);
반환�데이터:�파일이�오류없이�닫히면�0을�리턴
fopen() 함수로�파일을�열었으면�작업을�완료�후�반드시 fclose()함수로�닫아야�함
입력�파라미터:�파일포인터
입력�파라미터:
반환�데이터:�파일�포인터
Line Editor / fgets()
fgets() 함수�프로토타입:�
char* fgets(char *string, int n, FILE* stream);
반환�데이터:�읽은�문자열의�포인터,�더�읽을�내용이�없거나�에러�시�NULL 반환
입력�파라미터(3):�파일�데이터를�읽어�저장할�버퍼의�포인터�(string), 읽을�최대�문자�수�+1 (n),
오픈한 FILE 구조체�(_iobuf 구조체) 포인터 (stream)
#include <stdio.h>int main(){ char buf[20]; char *line; FILE *fptr = fopen(“data.txt”,”r”); if(fptr == NULL) { // 에러�처리 } else { while ((line = fgets(buf, sizeof(buf), fptr)) != NULL) { printf(“%s”,line);
} fclose(fptr);}return 0;
}
파일에서�읽은�데이터�포인터
파일�끝이나�‘\n’�문자까지�읽음�라인�끝(CR/LF)을�읽으면�개행�문자�‘\n’으로�변환�읽은�문자들�끝에�NULL�문자�추가
오픈한�파일에서�문자열을�한�줄씩�읽어옴
Line Editor: fputs()
fputs() 함수�프로토타입: int fputs(const char *string, FILE* stream);반환�데이터:�성공�시�0�또는�양수,�실패�시 EOF(-1)
입력�파라미터(2):�파일에�쓸�NULL로 끝나는�문자열�버퍼의�포인터 (string), 오픈한�FILE 구조체�(_iobuf 구조체)�포인터 (stream)
개방된�파일에�문자열을�라인�단위로�저장
int main( ){ char buf[255]; FILE *fptr = fopen("data1.txt", "w"); int result; if(fptr == NULL) { // 에러�처리�코드�
} else { for (int i = 0; i < 5; i++ ) { sprintf(buf, "[line:%d] %s \n", i+1, in[i]); result = fputs(buf, fptr); if (result == -1) printf ("file write error\n"); } fclose(fptr); } }
쓰기�모드
파일에�저장될�문자�한�줄�
개행�문자�‘\n’�문자를�라인�끝(CR/LF)로�변환
파일�포인터