str.md

#include<stdio.h>
#include<string.h>

struct schedule {
  int year;
  int month;
  int day;
  int hour;
  char title[100];
  struct schedule *next;
};

void update2years(struct schedule *target){
  target->year = target->year + 2;
}

void printSchedule(struct schedule target){
  printf("year:%04d, month:%02d, day:%02d, hour:%02d, title:%s\n", target.year, target.month, target.day, target.hour, target.title);
}


int main(void){
  struct schedule exam1;
  struct schedule exam2;

  exam1.year = 2021;
  exam1.month = 10;
  exam1.day = 30;
  exam1.hour = 10;
  exam1.next = &exam2;

  exam2.year = 2021;
  exam2.month = 12;
  exam2.day = 25;
  exam2.hour = 23;
  exam2.next = NULL;

  // -1: 末尾\0のため
  strncpy(exam1.title, "ハロウィン", sizeof(exam1.title)-1);
  strncpy(exam2.title, "クリスマス", sizeof(exam1.title)-1);

  printSchedule(exam1);
  printSchedule(*exam1.next);
  printSchedule(exam2);
  update2years(&exam1);
  update2years(&exam2);
  printSchedule(exam1);
  printSchedule(*exam1.next);
  printSchedule(exam2);
  return 0;
}

// 実行結果
year:2021, month:10, day:30, hour:10, title:ハロウィン
year:2021, month:12, day:25, hour:23, title:クリスマス
year:2021, month:12, day:25, hour:23, title:クリスマス
year:2023, month:10, day:30, hour:10, title:ハロウィン
year:2023, month:12, day:25, hour:23, title:クリスマス
year:2023, month:12, day:25, hour:23, title:クリスマス

参考

msymt/str.md