unit2.pas

用于开发税务票据管理的软件

unit Unit2;

interface
uses
  unit1;
Function GASDEV:real;
procedure AVEVAR(DATA:array of real; N:integer; var AVE, VAR1:real);

implementation
Function GASDEV:real;
var
   V1,V2,FAC,R:real;
begin
    If ISET^= 0 Then
    begin
      repeat
        V1:=2 * Random - 1;
        V2:=2 * Random - 1;
        R:=Sqr(V1) + Sqr(V2);
      until (R < 1);
      FAC:=Sqrt(-2 * Ln(R) / R);
      GSET^:=V1 * FAC;
      GASDEV:=V2 * FAC;
      ISET^:=1;
    end
    Else
    begin
      GASDEV:=GSET^;
      ISET^:=0;
    end;
end;

procedure AVEVAR(DATA:array of real; N:integer; var AVE, VAR1:real);
var
    J:integer;  S:real;
begin
    AVE:=0; 
    VAR1:=0;
    For J:=1 To N do
        AVE:=AVE + DATA[J];
    AVE:=AVE / N;
    For J:=1 To N do
    begin
        S:=DATA[J] - AVE;
        VAR1:=VAR1 + S * S;
    end;
    VAR1:=VAR1 / (N - 1);
end;
end.