#include <time.h> static int mday[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }; time_t mktime(const struct tm *tm){	int i;	time_t t = 0;	for(i=70; i<tm->tm_year; i++){		if(i%4 == 0)			t += 86400 * 366;		else			t += 86400 * 365;	}	for(i=0; i<tm->tm_mon; i++){		t += mday[i] * 86400;		if (tm->tm_year % 4 == 0 && i == 2)			t += 86400;	}	t += (tm->tm_mday-1) * 86400;	t += tm->tm_hour * 3600;	t += tm->tm_min * 60;	t += tm->tm_sec;	return t;}