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Find the distance between two points

erlang
Distance = distance({point, 34, 78}, {point, 67, -45}),
io:format("~.2f~n", [Distance]).
Distance = distance(point:new(34, 78), point:new(67, -45)),
io:format("~.2f~n", [Distance]).

Zero pad a number

Given the number 42, pad it to 8 characters like 00000042
erlang
Formatted = io_lib:format("~8..0B", [42]),
io:format("~8..0B~n", [42]).

Right Space pad a number

Given the number 1024 right pad it to 6 characters "1024  "
erlang
Formatted = io_lib:format("~-6B", [1024]),
io:format("~-6B~n", [1024]).

Format a decimal number

Format the number 7/8 as a decimal with 2 places: 0.88
erlang
Formatted = io_lib:format("~.2f", [7/8]),
io:format("~.2f~n", [7/8]).

Left Space pad a number

Given the number 73 left pad it to 10 characters "        73"
erlang
Formatted = io_lib:format("~10B", [73]),
io:format("~10B~n", [73]).

Generate a random integer in a given range

Produce a random integer between 100 and 200 inclusive
erlang
RandomInt = gen_rand_integer(100, 200),
99 + rand:uniform(101).

Generate a repeatable random number sequence

Initialise a random number generator with a seed and generate five decimal values. Reset the seed and produce the same values.
erlang
setRNG(RNGState),
io:format("~w~n", [lists:map(fun (_) -> gen_rand_integer(100, 200) end, lists:seq(1, 5))]),

setRNG(RNGState),
io:format("~w~n", [lists:map(fun (_) -> gen_rand_integer(100, 200) end, lists:seq(1, 5))]).