私はCの学習を始めましたが、問題に遭遇しました。
日付 ADT を作成しました。テストしてみたいと思います :)
基本的に、標準入力から文字列を読み込み、日付に変換して標準出力に出力したいと思います。
これらのファイルをコンパイルした後、次のエラーが発生しました。
datetest.c:15:45: error: incomplete definition of type 'struct date'
printf("Year: %d Month: %d Day: %d", d->year, d->month, d->day);
~^
./date.h:4:16: note: forward declaration of 'struct date'
typedef struct date Date;
私は何を間違っていますか？
日付.c:
#include "date.h"
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
struct date {
int day;
int month;
int year;
};
/*
* date_create creates a Date structure from `datestr`
* `datestr' is expected to be of the form "dd/mm/yyyy"
* returns pointer to Date structure if successful,
* NULL if not (syntax error)
*/
Date *date_create(char *datestr) {
Date *d = (Date *)malloc(sizeof(Date));
const char delimiter[2] = "/";
char *token;
if (d != NULL) {
token = strtok(datestr, delimiter);
d->day = atoi(token);
token = strtok(NULL, delimiter);
d->month = atoi(token);
token = strtok(NULL, delimiter);
d->year = atoi(token);
//printf("Day: %d Month: %d Year: %d\n", d->day, d->month, d->year);
//printf("Day: %p Month: %p Year: %p\n", *d->day, *d->month, *d->year);
}
return d;
};
/*
* date_duplicate creates a duplicate of `d'
* returns pointer to new Date structure if successful,
* NULL if not (memory allocation failure)
*/
Date *date_duplicate(Date *d) {
Date *dd = (Date *)malloc(sizeof(Date));
if (dd != NULL) {
dd->day = d->day;
dd->month = d->month;
dd->year = d->year;
}
return dd;
};
/*
* date_compare compares two dates, returning <0, 0, >0 if
* date1<date2, date1==date2, date1>date2, respectively
*/
int date_compare(Date *date1, Date *date2) {
if (date1->year < date2->year)
return -1;
else if (date1->year > date2->year)
return 1;
else {
if (date1->month < date2->month)
return -1;
else if (date1->month > date2->month)
return 1;
else {
if (date1->day < date2->day)
return -1;
else if (date1->day > date2->day)
return 1;
else
return 0;
}
}
};
/*
* date_destroy returns any storage associated with `d' to the system
*/
void date_destroy(Date *d) {
if (d != NULL)
free(d);
};
datetest.c:
#include "date.h"
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
int main() {
Date *d;
char buf[1024], *s;
while (fgets(buf, sizeof(buf), stdin) != NULL) {
if (!(d = date_create(buf))) {
fprintf(stderr, "Unable to create a date.\n");
return -1;
}
printf("Year: %d Month: %d Day: %d", d->year, d->month, d->day);
}
}
日付.h:
#ifndef _DATE_H_INCLUDED_
#define _DATE_H_INCLUDED_
typedef struct date Date;
/*
* date_create creates a Date structure from `datestr`
* `datestr' is expected to be of the form "dd/mm/yyyy"
* returns pointer to Date structure if successful,
* NULL if not (syntax error)
*/
Date *date_create(char *datestr);
/*
* date_duplicate creates a duplicate of `d'
* returns pointer to new Date structure if successful,
* NULL if not (memory allocation failure)
*/
Date *date_duplicate(Date *d);
/*
* date_compare compares two dates, returning <0, 0, >0 if
* date1<date2, date1==date2, date1>date2, respectively
*/
int date_compare(Date *date1, Date *date2);
/*
* date_destroy returns any storage associated with `d' to the system
*/
void date_destroy(Date *d);
#endif /* _DATE_H_INCLUDED_ */