Day of the week: Difference between revisions

...having a structured [https://en.wikipedia.org/wiki/SuperBASIC ''BASIC''] with MOD & DIV -and quite unlike the ZX81's "zeroeth-generation" BASIC that's rather like using a calculator which also is without an integer type. Even so, one should still put forth the effort into optimising the code for the task at hand, as done below - which if implemented for the ZX81's routine would make it finish in a fraction of a second, even in slow mode, as two multiplications by a (baker's) dozen are slower than one by 256, as well as that two divisions by multiples of 100 are much slower than a single divisionone by 16 as used in [gopher://sdf.org/0/users/retroburrowers/TemporalRetrology/cc/os ''Lachman's method''] of calculating the day of the week.