指针例题1

利用指针返回多个函数值

#include <stdio.h>
void month_day(int year, int yearday, int *pmonth, int *pday);

int main(void)
{
    int day, month, year, yearday;
    printf("input year and yearday:");
    scanf("%d %d", &year, &yearday);
    month_day(year, yearday, &month, &day);
    printf("%d-%d-%d
", year, month, day);

    return 0;
}
void month_day(int year, int yearday, int *pmonth, int *pday)
{
    int k, leap;
    int tab[2][13] = {
        {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
        {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
    };

    leap = ((year / 4 == 0) && (year / 100 != 0)) || (year % 400 == 0);

    for (k = 1; yearday > tab[leap][k]; k++)
    {
        yearday -= tab[leap][k];
    }

    *pmonth = k;
    *pday = yearday;
}