c语言：获取系统当前时间，设计年份计算月、日、时、分、秒等计算函数，然后调用这些函数之后显示你现在的时间。

#include<stdio.h>
#include<time.h>
#define u8 unsigned char
u8 isRunNian(int year);
int getYear(int *day);
int getMonth(int *day,int year);
int getMonthOrDay(int year,int month);
int getHour(long second);
int getMinute(long second);
int getSecond(long second); 
int main()
{
  int second = time(NULL);
  int day = (second/60/60+8)/24+1;
  int year= getYear(&day);
  printf("%4d年%2d月%2d日 %2d:%2d:%2d",
    year,getMonth(&day,year),day,
    getHour(second),getMinute(second),getSecond(second));
  return 0;
}
int getMonth(int *day,int year) 
{
  int month=1;
  while(*day>getMonthOrDay(year,month))
  {
    switch(month)
    {
      case 2:
        *day-=28;
        if(isRunNian(year))
        {
          *day-=1;
        }
        break;
      case 4:
      case 6:
      case 9:
      case 11:*day-=30;break;
      default:*day-=31;break;
    }
    month++;
  }
  return month;
}
int getMonthOrDay(int year,int month)
{
  int day;
  switch(month)
  {
    case 2:
      day=28;
      if(isRunNian(year))
      {
        day=29;
      }
      break;
    case 4:
    case 6:
    case 9:
    case 11:day=30;break;
    default:day=31;break;
  }
  return day;
}
int getYear(int *day)
{
  int year=1970;
  while(*day>365)//2000   366
  {
    *day-=365;
    if(isRunNian(year))
    {
      *day-=1;
    }
    year++;
  }
  if(*day==0)
  {
    year--;
    *day = 1;
  }
  return year;
}
u8 isRunNian(int year)
{
  if(year%400==0 || (year%4==0&&year%100!=0))
  {
    return 1;//代表是闰年 
  }
  return 0;//代表不是闰年 
}
int getHour(long second)
{
  //当前系统时间是北京时间，但是获取的是世界协调时 ，所以我们需要加上8， 
  return second/60/60%24+8;
}
int getMinute(long second)
{
  return second/60%60;
}
int getSecond(long second)
{
  return second%60;
}