求统计账户虚拟币的程序

#include <stdio.h>
#include <time.h>
#include <math.h>

int seconds_to_current( double* delta, int year, int mon, int day, int hour, int min, int sec )
{
    struct tm t;
    t.tm_year = year-1900;
    t.tm_mon = mon-1;
    t.tm_mday = day;
    t.tm_hour = hour;
    t.tm_min = min;
    t.tm_sec = sec;
    time_t time_beg = mktime(&t);
    if( time_beg == (time_t)(-1) )
        return -1;

    time_t time_end = time(NULL);
    if( time_end == (time_t)(-1) )
        return -2;

    *delta = difftime( time_end, time_beg );
    return 0;
}

void foo( int year, int mon, int day )
{
    double delta;
    int r = seconds_to_current( &delta, year, mon, day, 0, 0, 0 );
    if( r == -1 )
        printf( "%04d-%02d-%02d 不在 time_t 的表达范围之内.\n", year, mon, day );
    else if( r == -2 )
        printf( "当前日历时间 不在 time_t 的表达范围之内.\n" );
    else
    {
        double seconds = round( fabs(delta) ); // 四舍五入到整数秒
        long hms = lround( fmod(seconds, 24*60*60) );
        double days = round( (seconds-hms)/(24.*60*60) ); // 天数
        long hour_ = hms/3600;
        long min_ = hms%3600/60;
        long sec_ = hms%60;
        printf( "%s %.f天%ld时%ld分%ld秒\n", (delta<0?"未来":"迄今"), days, hour_, min_, sec_ );
    }
}

int main( void )
{
    foo( 2021, 10, 29 );

    foo( 2022, 10, 28 );
    foo( 2022, 10, 29 );
    foo( 2022, 10, 30 );

    foo( 2023, 10, 29 );
}