BlackFriday.c

代码

#include <stdio.h>
#define FIRSTDAY_OF_BEGINYEAR   (4)     // the first January of 1970 is Thursday
#define BEGIN_YEAR          (1970)  // begin with 1970
//#define TEST
地臩ꮽ
int find_leapyear(int beginyear, int endyear);
int main(int argc, char *argv[])
{
    int input_year = 0;
    int leapyear = 0;
    int before_full_day = 0;
    int weekday_of_inputyear_firstday = 0;
    int weekday_count = 0;
    int yearday_count = 1;
    int monthday_count = 1;
    int month_count = 1;
    int inputyear_leap_flag = 0;    // zero is normal year, one is leap year
    if( 1 == argc) {
        fprintf(stderr, "BlackFriday: error: without any year input!\n");
        return -1;
    }
    if( argc > 2) {
        fprintf(stderr, "BlackFriday: error: out of parameters!\n");
        fprintf(stdout, "BlackFriday: Please input only one year.\n");
        return -2;
    }
    input_year = ((unsigned int)argv[1][0]-48)*1000 + ((unsigned int)argv[1][1]-48)*100 + ((unsigned int )argv[1][2]-48)*10 + ((unsigned int )argv[1][3]-48)*1;
    if(input_year <= 1970 || input_year > 3000) {
        fprintf(stderr, "BlackFriday: error: out of allowed year!\n");
        fprintf(stderr, "BlackFriday: error: Please input a year within the range of 1970 to 3000.\n");
        return -3;
    }
    fprintf(stdout, "Input year is %d\n", input_year);
    if( ((input_year%4 == 0) && (input_year % 100 != 0)) || (input_year % 400 == 0)) {
        inputyear_leap_flag = 1;
        fprintf(stdout, "Input year leap year\n");
    }
    else {
        inputyear_leap_flag = 0;
        fprintf(stdout, "Input year normal year\n");
    }
    leapyear = find_leapyear(BEGIN_YEAR, input_year);
    fprintf(stdout, "before input year(without input year) have %d leap year\n", leapyear);
    before_full_day = leapyear * 366 + (input_year - BEGIN_YEAR - leapyear) * 365;
#ifdef TEST
    fprintf(stdout, "before_full_day is %d days\n", before_full_day);
#endif
    weekday_of_inputyear_firstday = (FIRSTDAY_OF_BEGINYEAR + (before_full_day % 7))%7;
#ifdef TEST
    fprintf(stdout, "weekday of %s firstday is %d\n", argv[1], weekday_of_inputyear_firstday);
#endif
    weekday_count = weekday_of_inputyear_firstday;
    fprintf(stdout, "In the year of %d :\n", input_year);
    while(month_count <= 12) // Begin a year loop
    {
    #ifdef TEST
        fprintf(stdout, "Calendar: weekday_count: %d, monthday_count: %2d, month_count: %2d, yearday_count: %3d\n", weekday_count, monthday_count, month_count, yearday_count);
    #endif
        if(monthday_count == 13) {
            if(weekday_count == 5)
                fprintf(stdout, "BlackFriday: Month %d . Day %d\n", month_count, monthday_count);
        }
        weekday_count ++;
        monthday_count ++;
        yearday_count ++;
        if(weekday_count > 6)
            weekday_count = 0;
        if(month_count == 1 || month_count == 3 || month_count == 5 || month_count == 7 || month_count == 8 || month_count == 10 || month_count == 12) {
            if(monthday_count > 31) {
                month_count ++;
                monthday_count = 1;
            }
        }
        else if(month_count == 4 || month_count == 6 || month_count == 9 || month_count == 11 ) {
            if(monthday_count > 30) {
                month_count ++;
                monthday_count = 1;
            }
        }
        else if(month_count == 2) {
            if(monthday_count > (28 + inputyear_leap_flag) ) {
                month_count ++;
                monthday_count = 1;
            }
        }
    }// End a year loop
    return 0;
}
int find_leapyear(int beginyear, int endyear) {
#ifdef TEST
    fprintf(stdout, "beginyear: %d, endyear: %d\n", beginyear, endyear);
#endif
    int year_count = beginyear;
    int leap_count = 0;
    do {
    #ifdef TEST
        fprintf(stdout, "leap_year: %d, year_count: %d\n", leap_count, year_count);
    #endif
        if ((year_count % 4 == 0)&&(year_count % 100 != 0) || (year_count % 400 == 0)) {
            fprintf(stdout, "%d is leap year\n", year_count);
            leap_count ++;
        }
        year_count ++;
    }while(year_count != endyear);
    return leap_count;
}