u7_3_1.cpp

《C++ Builder 5程序设计——基础教学篇》程序源代码2.

//--------------------  u7_3_1  -------------------------------------------------------
#include <vcl.h>
#pragma hdrstop

#include "u7_3_1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
Tf7_3_1 *f7_3_1;
//---------------------------------------------------------------------------
__fastcall Tf7_3_1::Tf7_3_1(TComponent* Owner)
    : TForm(Owner)
{
}
//---------------------------------------------------------------------------

void __fastcall Tf7_3_1::FormPaint(TObject *Sender)
{  int x,y,p_x,p_y;
   Canvas->Pen->Color=clBlack;
   Canvas->MoveTo(10,160);   Canvas->LineTo(310,160);
   Canvas->MoveTo(160,10);   Canvas->LineTo(160,310);
   Canvas->Pen->Color=clGreen;
   x=-100; y=x*x/100;
   p_x=x+160; p_y=-y+160;
   Canvas->MoveTo(p_x,p_y);
   for(x=-100;x<=100;x++)
   {  y=x*x/100;
      p_x=x+160;  p_y=-y+160;
      Canvas->LineTo(p_x,p_y);
   }
}
//---------------------------------------------------------------------------