unit Unit1;interfaceuses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls;type TForm1 = class(TForm) Button1: TButton; Button2: TButton; Button3: TButton; procedure Button1Click(Sender: TObject); procedure Button2Click(Sender: TObject); procedure Button3Click(Sender: TObject); end;var Form1: TForm1;implementation{$R *.dfm}uses ComObj;//执行数学公式的函数 RunForm://原理是借用 JavaScrip 脚本, 代码参考的是 Delphi 的 Format 函数;//第一个参数是公式, 公式中的常量要用 A B C D E F G H I J 十个大写字母依次标识;//第二个参数是参数组, 按顺序给出常量值(使用字符串的方式);//目前支持的函数在下面列着呢, 不过在这里为了和后面的参数区别只能都弄成小写.function RunForm(Formula: string; const Args: array of const): string;const f = 'acos = Math.acos;' + 'asin = Math.asin;' + 'atan = Math.atan;' + 'atan2 = Math.atan2;' + 'ceil = Math.ceil;' + 'cos = Math.cos;' + 'e = Math.E;' + 'exp = Math.exp;' + 'floor = Math.floor;' + 'ln10 = Math.LN10;' + 'ln2 = Math.LN2;' + 'log = Math.log;' + 'log10e = Math.LOG10E;' + 'log2e = Math.LOG2E;' + 'max = Math.max;' + 'min = Math.min;' + 'pi = Math.PI;' + 'pow = Math.pow;' + 'random = Math.random;' + 'round = Math.round;' + 'sin = Math.sin;' + 'sqrt = Math.sqrt;' + 'sqrt2 = Math.SQRT2;' + 'tan = Math.tan;';var Len, BufLen: Integer; Buffer: array[0..4095] of Char; script: OleVariant; i: Integer;begin for i := 0 to 9 do Formula := StringReplace(Formula, Char(i+65), '%' + IntToStr(i) + ':s', [rfReplaceAll]); BufLen := Length(Buffer); if Length(Formula) < (Length(Buffer) - (Length(Buffer) div 4)) then Len := FormatBuf(Buffer, Length(Buffer) - 1, Pointer(Formula)^, Length(Formula), Args) else begin BufLen := Length(Formula); Len := BufLen; end; if Len >= BufLen - 1 then begin while Len >= BufLen - 1 do begin Inc(BufLen, BufLen); Result := ''; SetLength(Result, BufLen);{$IFDEF UNICODE} Len := FormatBuf(PChar(Result), BufLen - 1, Pointer(Formula)^, Length(Formula), Args);{$ELSE} Len := FormatBuf(Pointer(Result)^, BufLen - 1, Pointer(Formula)^, Length(Formula), Args);{$ENDIF} end; SetLength(Result, Len); end else SetString(Result, Buffer, Len); try script := CreateOleObject('ScriptControl'); script.Language := 'JavaScript'; script.ExecuteStatement(f + 'str = ' + Result); Result := script.Eval('str'); except Result := 'Err'; end;end; {RunForm 函数结束}//测试一: 注意第二个参数要以字符串数组的方式给出procedure TForm1.Button1Click(Sender: TObject);var s: string;begin s := RunForm('(A + B) / (A - B)', ['6','4']); {这里 A = 6; B = 4}// s := RunForm('(6 + 4) / (6 - 4)', []); {这样也可以} ShowMessage(s); {5}end;//测试二: 使用的命令有大小写的区别procedure TForm1.Button2Click(Sender: TObject);var s: string;begin s := RunForm('sin(A) + cos(B) + tan(A)', ['0.8','0.9']); ShowMessage(s); {2.36860461622055}end;//测试三, 可以使用 JavaScript 的常量, 不过要用小写字母procedure TForm1.Button3Click(Sender: TObject);var s: string;begin s := RunForm('sqrt(pow(A, 2))', ['pi']); ShowMessage(s); {3.14159265358979}end;end.
object Form1: TForm1 Left = 0 Top = 0 Caption = 'Form1' ClientHeight = 130 ClientWidth = 206 Color = clBtnFace Font.Charset = DEFAULT_CHARSET Font.Color = clWindowText Font.Height = -11 Font.Name = 'Tahoma' Font.Style = [] OldCreateOrder = False Position = poDesktopCenter PixelsPerInch = 96 TextHeight = 13 object Button1: TButton Left = 64 Top = 24 Width = 75 Height = 25 Caption = 'Button1' TabOrder = 0 OnClick = Button1Click end object Button2: TButton Left = 64 Top = 55 Width = 75 Height = 25 Caption = 'Button2' TabOrder = 1 OnClick = Button2Click end object Button3: TButton Left = 64 Top = 86 Width = 75 Height = 25 Caption = 'Button3' TabOrder = 2 OnClick = Button3Click endend
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