C语言代码实现的万年历计算

C语言代码实现的万年历计算

#include 
#include 
#include 


int main(int a, char** date)
{
    int year = 0, month = 0, day = 0, week;
    int d, i, dm, dy, m2;
    char WEEK[9];
    if (a == 1)
        {
            printf ("\n ERROR! you forgot to enter the date you want to view\n");
            exit (0);
        }
    i = 0;
    d = -1;
    while (date[1][i])/*遍历传入的参数日期，计算出year，month，day*/
        {
            if ((date[1][i] == '/' || date[1][i] == '.') && d == -1)
                {
                    d = 0;
                    i++;
                    continue;
                }
            if ((date[1][i] == '/' || date[1][i] == '.') && d == 0)
                {
                    d = 1;
                    i++;
                    continue;
                }
            if (d == -1)
                {
                    year = year * 10 + (date[1][i] - '0');
                }
            if (d == 0)
                {
                    month = month * 10 + (date[1][i] - '0');
                }
            if (d == 1)
                {
                    day = day * 10 + (date[1][i] - '0');
                }
            i++;
        }
    if (month < 1 || month > 12) /*若月份传入错误数字*/
        {
            printf ("\n ERROR! the entered MONTH is invalid\n");
            exit (0);
        }
    if (year == 2000)
        {
            dy = 0;       /*年引起的星期差为0个*/
            m2 = 1;       /*2月引起的星期差为1个*/
            goto la_100;
        }
    if (year > 2000)
        {
            d = (year - 1 - 2000) / 4 - (year - 1 - 2000) / 100 + (year - 1 - 2000) / 400 + 1;
        }
    else
        {
            d = (year - 2000) / 4 - (year - 2000) / 100 + (year - 2000) / 400;
        }
    dy = (year - 2000) + d; /*** 该年 1月1号 到2000年1月1号的 " 星期差 " ***/
    if((year % 4 == 0 && year % 100 != 0) || (year % 100 == 0 && year % 400 == 0))
        {
            m2 = 1;
        }
    else
        {
            m2 = 0;   /*** 该年是否润 ***/
        }
la_100:                    /**** la_100 ****/
    /*** 该月以前的月所引起的 " 星期差 " ***/
    switch (month)
        {
        case 1:
            dm = 0;
            month = 31;
            break;   /*** month 在此存放该月天数 ***/
        case 2:
            dm = 3;
            month = d == 1 ? 29 : 28;
            break;
        case 3:
            dm = 3 + m2;
            month = 31;
            break;
        case 4:
            dm = 6 + m2;
            month = 30;
            break;
        case 5:
            dm = 1 + m2;
            month = 31;
            break;
        case 6:
            dm = 4 + m2;
            month = 30;
            break;
        case 7:
            dm = 6 + m2;
            month = 31;
            break;
        case 8:
            dm = 2 + m2;
            month = 31;
            break;
        case 9:
            dm = 5 + m2;
            month = 30;
            break;
        case 10:
            dm = m2;
            month = 31;
            break;
        case 11:
            dm = 3 + m2;
            month = 30;
            break;
        case 12:
            dm = 5 + m2;
            month = 31;
            break;
        }
    if (day < 0 || day > month)
        {
            printf ("\n ERROR! the entered DAY is invalid\n");
            exit (0);
        }
    week = (dy + dm + day - 1 + 6) % 7;
    if(week < 0)
        {
            week += 7;
        }
    if (day > 0)     /*** 判定查看类型 ***/
        {
            switch (week)
                {
                case 0:
                    strcpy (WEEK, "SUNDAY");
                    break;
                case 1:
                    strcpy (WEEK, "MONDAY");
                    break;
                case 2:
                    strcpy (WEEK, "TUESDAY");
                    break;
                case 3:
                    strcpy (WEEK, "WEDNESDAY");
                    break;
                case 4:
                    strcpy (WEEK, "THURSDAY");
                    break;
                case 5:
                    strcpy (WEEK, "FRIDAY");
                    break;
                case 6:
                    strcpy (WEEK, "SATURDAY");
                    break;
                }
            printf ("\n this day is %s  ( %d )\n\n OK!\n", WEEK, week);
        }
    else
        {
            week = ++week % 7;
            printf ("\n the calender of this month as following\n");
            printf ("\n *********************************\n");
            printf (" SUN  MON  TUE  WEN  THU  FRI  STA\n");
            for (i = 0; i < week; i++)
                {
                    printf ("     ");
                }
            for (i = 1; i <= month; i++)
                {
                    printf (" %2d  ", i);
                    week++;
                    if (week % 7 == 0 && i != month)
                        printf ("\n");
                }
            printf ("\n *********************************\n");
            printf ("\n OK!\n");
        }
    return 0;
}