Gregc. ha scritto:
G'day
I'm trying to work out the number of years since 1970, here is my code:
include <stdio.h>
#include <time.h>
const int SEC_IN_MIN = 60;
const int SEC_IN_HOUR = SEC_IN_MIN * 60;
const int SEC_IN_DAY = SEC_IN_HOUR * 24;
const int SEC_IN_YEAR = SEC_IN_DAY * 365;
int secToYear(int seconds) //Function Protoype
{
seconds = (SEC_IN_YEAR);
return (seconds);
}
main () {
time_t now = time(0);
printf("%i seconds since 1/1/1970\n",secToYear(now));
}
For some reason the answer is coming out as 1. Could someone offer me
some guidance.
Sure.
You could use this code:
---------------------------------------------------
#include <stdio.h>
#include <time.h>
#include <stdlib.h>
const int SEC_IN_YEAR = 31536000; /* Average seconds per year */
int main(void)
{
double years_r, months_r, days_r, hours_r, mins_r, secs_r;
/* "_r" stands for "raw" */
int years, months, days, hours, mins, secs;
time_t seconds;
seconds = time(NULL);
years_r = (double) seconds / SEC_IN_YEAR;
years = abs(years_r);
months_r = (years_r - (double)years) * 12;
months = abs(months_r);
days_r = (months_r - (double)months) * 30; /* Average days
per month... Who can write something better? */
days = abs(days_r);
hours_r = (days_r - (double)days) * 24;
hours = abs(hours_r);
mins_r = (hours_r - (double)hours) * 60;
mins = abs(mins_r);
secs_r = (mins_r - (double)mins) * 60;
secs = abs(secs_r);
printf("Years:\t%d\n", years);
printf("Months:\t%d\n", months);
printf("Days:\t%d\n", days);
printf("Hours:\t%d\n", hours);
printf("Mins:\t%d\n", mins);
printf("Secs:\t%d\n", secs);
printf("\n");
return 0;
}
---------------------------------------------------
It simply calculates years, months, days, hours, minutes and seconds
from 00:00:00 Jan 1, 1970 (also known as "Epoch").
If you just need the number of years, just delete all the code from
"months_r = (years_r ..." to "secs = abs(...". You should also fix the
variables declarations, and delete all those printfs...
No problem
David
P.S.: please tell me if this code is non-standard C... I've successfully
compiled it with `gcc -Wall -Wextra -ansi -pedantic'... (I'm just
learning C
)
