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delphi TParallel.For 老外得示例代码

作者:admin 来源: 日期:2020/3/6 20:53:02 人气: 标签:

 
program SystemThreadingTest;

{$APPTYPE CONSOLE}

uses
  System.Diagnostics,
  System.Threading;

const
  maxItems = 5000;
  DataSize = 100000;

procedure DoTest;
var
  matches: integer;
  i, j: integer;
  sw: TStopWatch;
  referenceStr: string;
begin
  Randomize;
  SetLength(referenceStr, DataSize);
  for i := low(referenceStr) to high(referenceStr) do
    referenceStr[i] := Chr(Ord('a') + Random(26));

  // parallel
  matches := 0;
  sw := TStopWatch.StartNew;
  TParallel.For(1, maxItems,
    procedure(Value: integer)
    var
      index: integer;
      found: integer;
    begin
      found := 0;
      for index := low(referenceStr) to high(referenceStr) do
        if (((Value mod 26) + Ord('a')) = Ord(referenceStr[index])) then
          inc(found);
      AtomicIncrement(matches, found);
    end);
  Writeln('Parallel matches: ', matches, ' in ', sw.ElapsedMilliseconds, 'ms');

  // serial
  matches := 0;
  sw := TStopWatch.StartNew;
  for i := 1 to maxItems do
    for j := low(referenceStr) to high(referenceStr) do
      if (((i mod 26) + Ord('a')) = Ord(referenceStr[j])) then
        inc(matches);
  Writeln('Serial matches: ', matches, ' in ', sw.ElapsedMilliseconds, 'ms');
end;

begin
  while True do
    DoTest;
end.