#include<stdio.h>
int leapyear(int y);
int getmonth(int y, int m);
int totalday(int y, int m);
int startday(int y, int m);
void calendar(int y, int m);
void title(int y, int m);/*计算是否是闰年*/
int leapyear(int y)
{if ((y % 4 == 0 && y % 100 != 0) || (y % 400 == 0))return 1;elsereturn 0;
}/*计算输入的年月天数*/
int getmonth(int y, int m)
{int days;if (m == 1 || m == 3 || m == 5 || m == 7 || m == 8 || m == 10 || m == 12)days = 31;if (m == 4 || m == 6 || m == 9 || m == 11)days = 30;if (m == 2){if (leapyear(y) == 1)days = 29;elsedays = 28;}return days;
}/*计算输入的年月天数距1900.1.1的相隔天数*/
int totalday(int y, int m)
{int totaldays = 0;int i;for (i = 1900; i < y; i++)//不计入输入年份的天数if (leapyear(i) == 1)totaldays += 366;elsetotaldays += 365;for (i = 1; i < m; i++)//不计算输入月份的天数totaldays += getmonth(y, i);return totaldays;
}/*确定输入月份的第一天是周几*/
int startday(int y, int m)
{int startdays;startdays = (1 + totalday(y, m)) % 7;//若取1900.1.1则天数为0而取到0(周天)所以应该+1(周一)return startdays;
}/*打印日历*/
void calendar(int y, int m)
{int dayss;int start;int i;dayss = getmonth(y, m);start = startday(y, m);for (i = 0; i < start; i++)//打印此月第一天前的空格printf("    ");for (i = 1; i <= dayss; i++)//打印此月的天数{printf("%4d", i);start++;if (start % 7 == 0)printf("\n");}printf("\n-----------------------------\n");
}/*打印日历标题*/
void title(int y, int m)
{printf("\n\t%d年%d月\n", y, m);printf("-----------------------------\n");printf("%4s%4s%4s%4s%4s%4s%4s\n", "日", "一", "二", "三", "四", "五", "六");
}/*主函数*/
int main()
{int y, m;int flag = 1;printf("----------");printf("   万年历   ");printf("----------");printf("\n1.万年历\n");printf("0.退出\n");do{printf("请选择:");scanf("%d", &flag);if (flag == 1){printf("\n请输入年份(1900后):");scanf("%d", &y);printf("请输入月份:");scanf("%d", &m);title(y, m);//标题calendar(y, m);//内容}else break;} while (flag == 1);//为假时退出return 0;      
}