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Today is Feb 29, –another leap year! I just found it is a good chance to raise the topic of logic operators again.
To determine if 2012 is a leap year, use the straightforward logic expression (demo is SAS, follow the pseudo code in the wiki page of leap year):
if mod(year,4) = 0 then do;
if mod(year,100) = 0 then do;
if mod(year,400) = 0 then is_leap = 1;
else is_leap = 0;
end;
else is_leap = 1;
end;
else leap=0;
while using logic operators (Boolean expression), only one line of codes needed:
is_leap = (mod(year,4) = 0) and
(
(mod(year,100) ^= 0) or (mod(year,400) = 0)
);
or using SAS bitwise logical operations:
is_leap=bor(band(mod(year,4) = 0,mod(year,100) ^= 0), mod(year,400) = 0)
| This post was kindly contributed by From a Logical Point of View » SAS - go there to comment and to read the full post. |