Long multiplication and result overflow

[pjerald]

What is important to Understand about these two functions when multiplying integers and converting it to Long value.

ONE WAY.
long convertDaysToMi lliseconds(int days) { return 1000*3600*24*da ys; }

ANOTHER WAY
long convertDaysToMi lliseconds(int days) { return 1000L*3600*24*d ays; }

OR
static final long MILLISECONDS_PE R_DAY = 24L*3600*1000;
long convertDaysToMi lliseconds(int days) { return days * MILLISECONDS_PE R_DAY; }

[JosAH]

What is important to Understand about these two functions when multiplying integers and converting it to Long value.

ONE WAY.
long convertDaysToMi lliseconds(int days) { return 1000*3600*24*da ys; }

ANOTHER WAY
long convertDaysToMi lliseconds(int days) { return 1000L*3600*24*d ays; }

OR
static final long MILLISECONDS_PE R_DAY = 24L*3600*1000;
long convertDaysToMi lliseconds(int days) { return days * MILLISECONDS_PE R_DAY; }

Erm, those are *three* functions, not two. No need to worry though, I'm off by one
almost all the time. (the first method can cause int overflow).

kind regards,

Jos ;-)