스택

LIFO에 따라 자료를 배열.

프링글스같은 느낌임(공장에서 가장 마지막에 넣은 과자를 우린 가장 먼저 쳐먹지)

---

배열 이용

#include <cstdio>
int main()
{
    int num[100], count = 0;
    char command;
    int comnum;
    while (1)
    {
        printf("입력 - i / 삭제 - d\n : ");
        scanf("%c", &command);
        if (command == 'i')
        {
            printf("입력할 자연수 : ");
            scanf("%d", &comnum);
            num[count++] = comnum;
        }
        else if (command == 'd' && count > 0)
            printf("%d\n", num[--count]);
        while (getchar() != '\n');
    }
}

---

연결리스트 이용

#include <cstdio>
struct node
{
    node *next;
    node *prev;
    int data;
};
node *head, *foot;
void init();
int main()
{
    init();
    char command;
    int comnum;
    node *newnode;
    while (1)
    {
        printf("입력 - i / 삭제 - d\n : ");
        scanf("%c", &command);
        if (command == 'i')
        {
            printf("입력할 자연수 : ");
            scanf("%d", &comnum);
            newnode = new node;
            newnode->next = foot;
            newnode->prev = foot->prev;
            newnode->prev->next = newnode;
            foot->prev = newnode;
            newnode->data = comnum;
        }
        else if (command == 'd')
        {
            newnode = foot->prev;
            if (newnode->data != -1)
            {
                newnode->prev->next = foot;
                foot->prev = newnode->prev;
                printf("%d\n", newnode->data);
                delete newnode;
            }
        }
        newnode = head->next;
        while (getchar() != '\n');
    }
}
void init()
{
    head = new node;
    foot = new node;
    head->next = foot->next = foot;
    head->prev = foot->prev = head;
    head->data = foot->data = -1;
}