纯C语言实现万年历

纯C语言实现万年历需要先看清适用场景和关键步骤，避免只记结论却忽略实际限制。

一、项目介绍

需求和功能是用纯C语言实现一个可以属于年份，属于一个年份就可以显示该年各个月份的日历，如同日历一般，每个月当中每天对应的星期均可查看，即万年历，要求格式整齐，星期对照直观。

二、运行截图

启动效果：

输入一个符合条件的年份后：

三、代码思路

首先构思整个需求的思路，即接收一个年份，然后打印该年各个月的日历，其难点在于知道每个月的第一天是星期几，后面的天数即可依次循环打印即可

本项目需要知道的其余几个小技术点和易出错点：

1.判断闰年，这里判断不对易出错，方法是能被4整除并且能被100整除，或者是直接能被400整除。

2.能判断出某月某天是这一年的第几天，方法是把这个月前面的天数+这个月的天数

3.如何知道每个月多少天，这个除了二月其余月是固定的，可以提前写好（二月可以定28天也可以29天），特殊判定这年是否是闰年，来决定是否单独加一天或减一天。

4.格式问题，熟练使用宏定义、switch判断即可，做好实际数字与英文的对应打印

四、完整源码

测试编译器：VC6.0，代码量约近400行，如下：

#include<stdio.h>#include<windows.h> #define Mon 1#define Tues 2#define Wed 3#define Thur 4#define Fri 5#define Sat 6#define Sun 0 #define January_days 31#define February_days 28#define March_days 31#define April_days 30#define May_days 31#define June_days 30#define July_days 31#define August_days 31#define September_days 30#define October_days 31#define November_days 30#define December_days 31 #define first1month January_days#define first2month January_days+February_days#define first3month January_days+February_days+March_days#define first4month January_days+February_days+March_days+April_days#define first5month January_days+February_days+March_days+April_days+May_days#define first6month January_days+February_days+March_days+April_days+May_days+June_days#define first7month January_days+February_days+March_days+April_days+May_days+June_days +July_days#define first8month January_days+February_days+March_days+April_days+May_days+June_days +July_days+August_days#define first9month January_days+February_days+March_days+April_days+May_days+June_days +July_days+August_days+September_days#define first10month January_days+February_days+March_days+April_days+May_days+June_days +July_days+August_days+September_days+October_days#define first11month January_days+February_days+March_days+April_days+May_days+June_days +July_days+August_days+September_days+October_days+November_days int known_weekday = Tues;int known_year = 1901;int konwn_month = 1;int known_day = 1; int day_count(int month){switch(month){case 1: return 0;break;case 2: return first1month;break;case 3: return first2month;break;case 4: return first3month;break;case 5: return first4month;break;case 6: return first5month;break;case 7: return first6month;break;case 8: return first7month;break;case 9: return first8month;break;case 10: return first9month;break;case 11: return first10month;break;case 12: return first11month;break;}}  /*char * month_name(int month){switch(month){case 1:return "January";break;case 2:return "February";break;case 3:return "March";break;case 4:return "April";break;case 5:return "May";break;case 6:return "June";break;case 7:return "July";break;case 8:return "August";break;case 9:return "September";break;case 10:return "October";break;case 11:return "November";break;case 12:return "December";break;default:break;}}*/ char * month_name(int month){switch(month){case 1:return "一月";break;case 2:return "二月";break;case 3:return "三月";break;case 4:return "四月";break;case 5:return "五月";break;case 6:return "六月";break;case 7:return "七月";break;case 8:return "八月";break;case 9:return "九月";break;case 10:return "十月";break;case 11:return "十一月";break;case 12:return "十二月";break;default:break;}} /*按格式打印某年某月名称*/void first_line_print(int month, int year){//printf("%20s %d n",month_name(month),year);printf("%8d年 %s n",year, month_name(month));} /*按格式打印星期名称*/void week_print(){//printf("%-6s%-6s%-6s%-6s%-6s%-6s%-6sn","Sun.", "Mon.", "Tues.", "Wed.", "Thur.", "Fri.", "Sat.");printf("%-3s%-3s%-3s%-3s%-3s%-3s%-3sn","日", "一", "二", "三", "四", "五", "六");} /*计算该年该月份与已知日子之间的距离天数*/int date_distance_count(int month, int year){int leap_year_count = 0;int i;int distance;if (year > known_year){for (i=known_year; i<year; i++){if(((i%4 == 0) && (i%100 != 0) ) || (i%400 == 0)){leap_year_count++;}}if (month > 2){if(((year%4 == 0) && (year%100 != 0) ) || (year%400 == 0)){leap_year_count++;}}}elseif (year == known_year){if (month > 2){leap_year_count = 1;}}distance = (year - known_year)*365 + leap_year_count + day_count(month);return distance;} /*确定该月份第一天是星期几*/int makesure_firstday_weekday(int month, int year){int date_distance = 0;int weekday;date_distance = date_distance_count(month, year);weekday = (known_weekday + date_distance)%7;return weekday;} /*依次打印出该月份的日子*/void print_in_turn(int month, int firstday, int year){int i = 1;int weekday;switch(firstday){case Sun:break;case Mon:printf("%-3s","");break;case Tues:printf("%-6s","");break;case Wed:printf("%-9s","");break;case Thur:printf("%-12s","");break;case Fri:printf("%-15s","");break;case Sat:printf("%-18s","");break;}switch(month){case 1:case 3:case 5:case 7:case 8:case 10:case 12:{for(i=0; i<31; i++){weekday = (firstday + i)%7;printf("%-3d",i+1);if(weekday == Sat){printf("n");}}break;}case 2:{if(((year%4 == 0) && (year%100 != 0) ) || (year%400 == 0)) /*闰年*/{for(i=0; i<29; i++){weekday = (firstday + i)%7;printf("%-3d",i+1);if(weekday == Sat){printf("n");}}break;}else /*平年*/{for(i=0; i<28; i++){weekday = (firstday + i)%7;printf("%-3d",i+1);if(weekday == Sat){printf("n");}}break;}}case 4:case 6:case 9:case 11:{for(i=0; i<30; i++){weekday = (firstday + i)%7;/*计算该天是星期几*/printf("%-3d",i+1);if(weekday == Sat){printf("n");/*如果是星期六，则换行*/}}break;}}} void date_print(int month, int year){int firstday;firstday = makesure_firstday_weekday(month, year);print_in_turn(month, firstday, year);printf("n");} void main_month(int month, int year){first_line_print(month, year);week_print();date_print(month, year);printf("nn");} void main_calendar(int year){int i;for(i=1; i<=12; i++){main_month(i, year);}} int main(){int year;system("title c语言研究中心 www.dotcpp.com");printf("请输入年份：year = ");scanf("%d",&year);printf("n");while(year < 1902){printf("请输入大于1901的年份n");printf("请输入年份：year = ");scanf("%d",&year);printf("n");}main_calendar(year);scanf(" ");return 0;}