程序代码：

typedef struct {
  int year, month, day;
} Date;

Date* CreateDate(int year, int month, int day){
     Date *date = (Date*)malloc(sizeof(Date));
     date->year=year;
     date->month=month;
     date->day=day;
     return date;
}
void DestroyDate(Date** p){
     free(*p); 
     *p = NULL;
}
Date* CopyDate(const Date* date){
    Date *a; 
    a = (Date *) malloc(sizeof(Date)); 
    *a = *date;
    return a; 
}

int GetYear(const Date* date){
    return date->year;
}

void SetYear(Date* date, int year){
    date->year=year;
}
void SetDate(Date* date, int year, int month, int day){
    date->year=year;
    date->month=month;
    date->day=day;
    
}