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#include <stdio.h>
#include <stdlib.h>

/*
 * https://ja.wikipedia.org/wiki/連結リスト#.E9.80.A3.E7.B5.90.E3.83.AA.E3.82.B9.E3.83.88.E3.81.A8.E9.85.8D.E5.88.97
 */

typedef struct node {
    int key;
    struct node *next;
} Node;

Node *head;

void insert(int);
void print_keys();
int find(int);
void free_list();

int main(){
    int i;
    head = malloc(sizeof (struct node));
    head->key = -1;
    head->next = NULL;

    for(i=0;i<10;i++){
        insert(i);
    }

    printf("==find==\n");
    printf("5: %d\n", find(5));
    printf("15: %d\n", find(15));
    printf("\n");

    print_keys();

    free_list();

    return 0;
}

void insert(int key){
    Node *new_node = malloc(sizeof (struct node));
    new_node->key = key;

    new_node->next = head->next;
    head->next = new_node;
}

void print_keys(){
    Node *p;

    for(p=head->next; p->next != NULL; p=p->next){
        printf("%d ", p->key);
    }

    printf("\n");
}

int find(int key){
    Node *p;

    for(p=head->next; p->next != NULL; p=p->next){
        if(p->key == key){
            return 1;
        }
    }

    return 0;
}

void free_list(){
    Node *p, *tmp;
    p = head;

    while(p != NULL){
        tmp = p->next;
        free(p);
        p = tmp;
    }
}