C语言实现格林威治时间转北京时间+根据日期计算星期几

港控/mmm° 2023-02-23 08:21 65阅读 0赞

# C语言实现格林威治时间转北京时间+根据日期计算星期几 #

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**【北京时间=GMT时间+8小时】**

*日期数据结构定义：*

typedef struct
    { 
    	uint16_t year;
    	uint8_t month;
    	uint8_t day;
    	uint8_t hour;
    	uint8_t minute;
    	uint8_t second;
    }time_t;

**转换实现：**

void UTCToBeijing(time_t* time)
    { 
    	uint8_t days = 0;
    	if (time->month == 1 || time->month == 3 || time->month == 5 || time->month == 7 || time->month == 8 || time->month == 10 || time->month == 12)
    	{ 
    		days = 31;
    	}
    	else if (time->month == 4 || time->month == 6 || time->month == 9 || time->month == 11)
    	{ 
    		days = 30;
    	}
    	else if (time->month == 2)
    	{ 
    		if ((time->year % 400 == 0) || ((time->year % 4 == 0) && (time->year % 100 != 0))) /* 判断平年还是闰年 */
    		{ 
    			days = 29;
    		}
    		else
    		{ 
    			days = 28;
    		}
    	}
    	time->hour += 8;                 /* 北京时间比格林威治时间快8小时 */
    	if (time->hour >= 24)            /* 跨天 */
    	{ 
    		time->hour -= 24;
    		time->day++;
    		if (time->day > days)        /* 跨月 */
    		{ 
    			time->day = 1;
    			time->month++;
    			if (time->month > 12)    /* 跨年 */
    			{ 
    				time->year++;
    			}
    		}
    	}
    }

**【根据日期计算周几】：**

/// 返回值：1-7，对应周一到周天
    uint8_t GetWeekDayNum(uint32_t year, uint8_t month, uint8_t day)
    { 
      uint32_t weekday = 0U;
    
      if (month < 3U)
      { 
    	/*D = { [(23 x month)/9] + day + 4 + year + [(year-1)/4] - [(year-1)/100] + [(year-1)/400] } mod 7*/
    	weekday = (((23U * month) / 9U) + day + 4U + year + ((year - 1U) / 4U) - ((year - 1U) / 100U) + ((year - 1U) / 400U)) % 7U;
      }
      else
      { 
    	/*D = { [(23 x month)/9] + day + 4 + year + [year/4] - [year/100] + [year/400] - 2 } mod 7*/
    	weekday = (((23U * month) / 9U) + day + 4U + year + (year / 4U) - (year / 100U) + (year / 400U) - 2U) % 7U;
      }
    
      if(weekday == 0)
      { 
    	  weekday = 7;
      }
    
      return (uint8_t)weekday;
    }

ends…