aa.cpp

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
typedef struct student {
	int id;
	char name[20];
	student *next;
}student;
int main() {
	// 예제 1
	/*int n;
	scanf("%d", &n);
	int *arr = (int*)malloc(n * sizeof(int));
	for (int i = 0; i < n; i++) {
	*(arr + i) = i;
	printf("%d\n", *(arr + i));
	}*/
	// 예제 2
	struct student hanjae;
	hanjae.id = 2014210110;
	strcpy(hanjae.name, "제한재");
	printf("학번: %d, 이름: %s\n", hanjae.id, hanjae.name);
	// 예제 3
	struct student *study = (struct student*)malloc(9 * sizeof(struct student));
	study->id = 2018320202;     // (study+0) == study
	strcpy(study->name, "김재민");
	(study + 1)->id = 2018320210;
	strcpy((study + 1)->name, "정윤지");
	printf("%d %d\n", (study + 1)->id, study[1].id); // study[1].id -> (*(study+1)).id

													 // 예제 4
	hanjae.next = &study[0]; // study[0] : 재민
							 // hanjae.next = study;
	study[0].next = &study[1]; // 정윤지
	study[1].next = NULL;
	student* t = &hanjae;
	printf("예제 4\n");
	while (t != NULL) {
		printf("%d %s\n", t->id, t->name);
		t = t->next;
	}
	// 예제 5
	student *gunwoo = (student*)malloc(sizeof(student));
	gunwoo->id = 2016320143;
	strcpy(gunwoo->name, "이건우");
	gunwoo->next = hanjae.next; // 김재민
	hanjae.next = gunwoo;
	
	student* start = &hanjae;
	t = start;
	printf("예제 5\n");
	while (t != NULL) {
		printf("%d %s\n", t->id, t->name);
		t = t->next;
	}
	// 예제 6
	// gunwoo->next = &study[1];
	gunwoo->next = gunwoo->next->next;
	printf("예제 6\n");
	t = start;
	while (t != NULL) {
		printf("%d %s\n", t->id, t->name);
		t = t->next;
	}

	// 예제 7
	printf("예제 7\n");
	// 출력
	t = start;
	while (t != NULL) {
		printf("%d %s\n", t->id, t->name);
		t = t->next;
	}
	printf("==========\n");
	while (true) {
		/*student nn; // -> 이런식으로 하면 메모리 주소가 항상 같더라.
		student *new_student = &nn; */
		student *new_student = (student*)malloc(sizeof(student));
		printf("새 학생의 메모리 주소 = %x\n", new_student);
		printf("학번을 입력하세요 = ");
		scanf("%d", &new_student->id);
		if (new_student->id == 0) break;

		printf("이름을 입력하세요 = ");
		scanf("%s", new_student->name);
		new_student->next = NULL;

		t = start;
		if (new_student->id < start->id) {
			// 맨 앞에 학생이 추가될때
			new_student->next = start;
			start = new_student;
		}
		else {
			// 중간에 학생이 추가될때
			while (t->next != NULL) {
				if (t->id < new_student->id && new_student->id < t->next->id)
					break;
				t = t->next;
			}
			new_student->next = t->next;
			t->next = new_student;
		}
	}
	printf("========\n");
	t = start;
	while (t != NULL) {
		printf("%d %s\n", t->id, t->name);
		t = t->next;
	}

	// 예제 8
	printf("예제 8\n");
	int num;
	printf("지울 학생의 학번을 입력 = ");
	scanf("%d", &num);

	if (start->id == num) {
		start = start->next;
	}
	else {
		t = start;
		while (t != NULL) {
			if (t->next != NULL && t->next->id == num) {
				t->next = t->next->next;
				break;
			}
		}
	}
	printf("========\n");
	t = start;
	while (t != NULL) {
		printf("%d %s\n", t->id, t->name);
		t = t->next;
	}
}