鐃宿わ申鐃緒申鐃淑ら、鐃盾う鐃緒申鐃緒申鐃駿わ申鐃緒申鐃緒申鐃緒申鐃処う鐃祝書いてみわ申鐃緒申

鐃熟わ申鐃駿にっわ申# - C鐃緒申鐃緒申鐃�tail鐃獣ぽわ申鐃緒申里鐃緒申
鐃殉わ申鐃緒申鐃緒申鐃緒申鐃舜科わ申C鐃緒申鐃緒申離謄鐃緒申箸鐃緒申鐃緒申襦�C鐃緒申鐃緒申覆鐃緒申鐃緒申覆泙辰鐃緒申鐃緒申箸鐃淑わ申鐃緒申鐃緒申鐃緒申鐃初，鐃竣わ申鐃出わ申鐃粛ば￥申鐃銃わ申鐃夙で￥申10鐃峻醐申鐃緒申鐃緒申tail鐃緒申颪い討澆鐃緒申鐃緒申焚鐃緒申離鐃緒申鐃緒申鐃緒申鐃�

鐃殉わ申鐃熟￥申main()鐃緒申鐃緒申鐃緒申鐃初。鐃緒申発鐃緒申鐃緒申鐃緒申鐃叔は芸わ申無鐃緒申鐃塾で￥申鐃峻随申鐃盾オ鐃竣ワ申鐃緒申鐃夙わ申鐃銃誌申鐃緒申任鐃緒申鐃処う鐃祝わ申鐃銃みわ申鐃緒申

tail.c 
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_CHARS_IN_LINE 1024
#include "queue.h"

char *new_string(const char *str){
    char *new = (char *)malloc(strlen(str)+1);
    if (new == NULL) DIE_OUT_OF_MEMORY;
    strcpy(new, str); /* it's okay not to use strncpy */
    return new;
}

void usage(const char *str){
    fprintf(stderr, "usage: %s [-n] inputfile\n", str);
    exit(2);
}

int print_atom(void *str){
    return printf("%s", (char *)str);
}

int main(int argc, char **argv){
    char buf[MAX_CHARS_IN_LINE];
    int nline = 10;
    queue *q;
    FILE *fp;

    if (argc < 2) usage(argv[0]);
    if (argv[1][0] == '-'){
        nline = atoi(argv[1]+1);
        if (!nline) usage(argv[0]);
    }
    if ((fp = fopen(argv[argc-1],"r")) == NULL){
        fprintf(stderr, "%s : %s\n", argv[argc-1], strerror(2));
        exit(2);
    }
    q = new_queue(nline);
    while (fgets(buf, MAX_CHARS_IN_LINE, fp)) {
        enqueue(q, new_string(buf));
    }
    traverse_queue(q, print_atom);
    del_queue(q);
    exit(0);
}

鐃緒申鐃銃わ申鐃縮り、

  • 鐃緒申鐃緒申鐃緒申端鐃緒申鐃淑ら、鐃緒申鐃緒申未房鐃緒申泙鐃緒申腓�鐃緒申鐃祝￥申
  • -Wall鐃緒申弔鐃緒申鐃�compile鐃緒申鐃銃わ申鐃緒申鐃緒申鐃�warning鐃緒申鐃出なわ申鐃処う鐃緒申鐃緒申鐃獣わ申鐃緒申cast鐃緒申
  • queue鐃塾関わ申鐃舜随申鐃緒申鐃緒申蓮鐃�queue.h鐃緒申鐃緒申鐃緒申鐃宿わ申鐃出わ申鐃銃わ申鐃暑。
  • traverse_queue()鐃緒申鐃緒申鐃旬￥申C鐃叔わ申鐃緒申鐃舜随申鐃緒申鐃獣ぽわ申鐃緒申鐃緒申覆鐃緒申鐃淑わ申鐃夙わ申鐃緒申鐃緒申箸鐃緒申董鐃緒申鐃獣とわ申C鐃祝わ申lambda鐃熟なわ申鐃塾わ申鐃緒申鐃宿￥申

鐃緒申鐃緒申如鐃�queue.h鐃熟以駕申鐃塾とわ申鐃所。

queue.h 
#define DIE_OUT_OF_MEMORY { fprintf(stderr, "Out of memory!\n"); exit(-1); }

struct list {
    void *car, *cdr;
};
typedef struct list list;

struct queue{
    int size, max;
    list *head, *tail;
};
typedef struct queue queue;

list *new_list(void *atom){
    list *new = (list *)malloc(sizeof(list));
    if (new == NULL) DIE_OUT_OF_MEMORY;
    new->car = atom;
    new->cdr = NULL;
    new->head = new->tail = NULL; /* shiro-san, thanx */
    return new;
}

void del_list(list *l){
    if (l == NULL) return;
    if (l->car) free(l->car);
    free(l);
}

queue *new_queue(int max){
    queue *new = (queue *)malloc(sizeof(queue));
    if (new == NULL) DIE_OUT_OF_MEMORY;
    new->max  = max;
    new->size = 0;
    return new;
}

list *dequeue(queue *q){
    list *head = q->head;
    if (head) {
        q->head = q->head->cdr;
        q->size--;
    }
    return head;
}

int enqueue(queue *q, void *atom){
    list *l = new_list(atom);
    if (q->size == q->max) del_list(dequeue(q));
    if (q->size == 0) {
        q->head = q->tail = l;
        q->head->cdr = q->tail;
    }else{
        q->tail->cdr = l;
        q->tail = l;
    }
    q->size++;
    return q->size;
}

void del_queue(queue *q){
    list *l;
    if (q == NULL) return;
    while((l = dequeue(q)) != NULL){ 
        del_list(l); 
    }
    free(q);
}

void traverse_queue(queue *q, int (*callback)(void *)){
    list *l;
    for (l = q->head; l; l = l->cdr) callback(l->car);
}
  • car,cdr鐃夙わ申鐃緒申鐃塾は種申味:)
  • void *鐃淑ので￥申鐃駿わ申鐃緒申鐃緒申鐃緒申鐃緒申鐃緒申鐃緒申覆鐃�tail鐃淑鰹申鐃祝わ申箸鐃緒申鐃緒申鐃緒申鐃緒申鐃緒申
  • 鐃緒申鐃緒申鐃緒申鐃緒申car鐃緒申list鐃緒申屬蕾種申鐃緒申襪鰹申箸蝋鐃塾醐申鐃緒申討鐃緒申覆鐃緒申鐃緒申鐃緒申鐃緒申鐃緒申鐃緒申任鐃�queue鐃緒申鐃緒申鐃緒申任鐃緒申鐃出よい鐃塾でわ申鐃緒申鐃緒申鐃駿でわ申鐃緒申鐃緒申鐃緒申鐃緒申鐃緒申
  • queue鐃祝まつわ申鐃緒申鐃緒申楼鐃緒申未鐃緒申鐃緒申鐃塾で￥申鐃夙わ申鐃緒申鐃熟刻申造鐃薯気にわ申鐃緒申必鐃竣わ申鐃緒申鐃殉わ申覆鐃緒申鐃緒申鐃緒申鐃緒申童鐃緒申鐃緒申弌鐃�enqueue鐃緒申鐃緒申鐃�element鐃緒申必鐃緒申malloc()鐃緒申鐃曙た鐃緒申里任鐃緒申鐃夙わ申鐃緒申鐃緒申鐃夙わ申鐃緒申
  • traverse_queue()鐃緒申callback()鐃緒申void鐃叔わ申茲�鐃獣わ申鐃緒申鐃淑￥申

鐃緒申鐃淑みに￥申鐃瞬ふつわ申鐃緒申Haskell鐃旬」わ申tail鐃熟￥申鐃緒申鐃所ー浪鐃書型￥申鐃緒申鐃緒申鐃緒申鐃駿わ申鐃夙まわ申Haskell鐃塾わ申鐃緒申鐃竣はわ申鐃殉わ申覆鐃緒申董鐃�Perl鐃叔わ申

perl -e 'print reverse((reverse <>)[0..9])'

鐃叔緒申鐃緒申討鐃緒申泙鐃緒申鐃�

Dan the Occasional C Programmer