implementation
//PROGRAM D1R2
//Driver for routine LUBKSB,LUDCMP
uses
  unit2;
  {$R *.DFM}
procedure TForm1.Button1Click(Sender: TObject);
var
    A,A1:matrx2;
    B,INDX,X:Array[0..3] of real;
    I,J:Integer;     D:real;
    F:TextFile;
const
    s1='%10.1f'; N = 3;
begin
  setlength(A,4,4);
  setlength(A1,4,4);
  //輸入已知的方程組的系數矩陣
  A[1, 1]:=1;   A[1, 2]:=2;   A[1, 3]:=3;
  A[2, 1]:=2;   A[2, 2]:=2;   A[2, 3]:=3;
  A[3, 1]:=3;   A[3, 2]:=3;   A[3, 3]:=3;
  //輸入已知的方程組的右端向量B
  B[1]:=1;
  B[2]:=2;
  B[3]:=3;
  //輸出計算結果到文件
  AssignFile(F, 'd:\delphi_shu\p1\d1r2.dat');
  Rewrite(F);
  Writeln(F, '已知的方程組的右端向量');
  For I:= 1 To 3 do
    Writeln(F,Format(s1,[B[I]]));
  For I:=1 To N do
    begin
      For J:=1 To 3 do
        A1[I, J]:=A[I, J];
    end;
  LUDCMP(A1, N, INDX, D);
  For I:= 1 To N Do
    X[I]:=B[I];
  LUBKSB(A1, N, INDX, X);
  Writeln(F, '計算出的方程組的解');
  For I:= 1 To 3 do
    Writeln(F,Format(s1,[X[I]]));
  Writeln(F, '將計算出的解B乘以系數矩陣，以驗證計算結果正確');
  For I:=1 To N do
    begin
      B[I]:=0;
      For J:=1 To N do
        B[I]:=B[I] + A[I, J] * X[J];
    end;
  For I:= 1 To 3 do
    Writeln(F,Format(s1,[B[I]]));
  CloseFile(F);
  //屏幕顯示計算結果
  memo1.Lines.LoadFromFile('d:\delphi_shu\p1\d1r2.dat');
end;