One of n lines in a file: Difference between revisions

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Note: You may choose a smaller number of repetitions if necessary, but mention this up-front.
Note: You may choose a smaller number of repetitions if necessary, but mention this up-front.

=={{header|Ada}}==

<lang Ada>with Ada.Text_IO, Ada.Numerics.Float_Random;

procedure One_Of_N is

Num_Of_Lines: constant Positive := 10;

package Rnd renames Ada.Numerics.Float_Random;
Gen: Rnd.Generator; -- used globally

function Choose_One_Of_N(Last_Line_Number: Positive) return Natural is
Current_Choice: Natural := 0;
begin
for Line_Number in 1 .. Last_Line_Number loop
if (Rnd.Random(Gen) * Float(Line_Number) <= 1.0) then
Current_Choice := Line_Number;
end if;
end loop;
return Current_Choice;
end Choose_One_Of_N;

Results: array(1 .. Num_Of_Lines) of Natural := (others => 0);
Index: Integer range 1 .. Num_Of_Lines;

begin
Rnd.Reset(Gen);
for I in 1 .. 1_000_000 loop -- compute results
Index := Choose_One_Of_N(Num_Of_Lines);
Results(Index) := Results(Index) + 1;
end loop;

for R in Results'Range loop -- output results
Ada.Text_IO.Put(Integer'Image(Results(R)));
end loop;
end One_Of_N;</lang>

Example output:<pre> 100104 100075 99761 99851 100457 100315 100101 99557 99678 100101</pre>


=={{header|C}}==
=={{header|C}}==
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