Question

请问如何用C++画出函数的图像。

有一个函数y=1/(1+x*x);用C++应该怎样画出

Answer 1

可以直接调用CodeBlocks,MinGW,Win SDK
2. CodeBlocks可以创建 Win32 GUI Project
3. resource.h
#include <windows.h>
// ID of Main Dialog
#define DLG_MAIN 101
4. resource.rc
#include "resource.h"
DLG_MAIN DIALOGEX 6, 5, 194, 106
CAPTION "Code::Blocks Template Dialog App"
FONT 8, "Tahoma"
5. main.cpp
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include<stdlib.h>
#include<string.h>
#include "resource.h"
HINSTANCE hInst;
BOOL CALLBACK DialogProc(HWND hwndDlg, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
  HDC hDC; //定义指向设备描述表的句柄
  HBRUSH hBrush; //定义指向画刷的句柄
  HPEN hPen; //定义指向画笔的句柄
  PAINTSTRUCT PtStr; //定义指向包含绘图信息的结构体变量
  switch(uMsg)
  {
    case WM_PAINT:
     hDC=BeginPaint(hwndDlg,&PtStr);
     SetMapMode(hDC,MM_ANISOTROPIC); //设置映像模式
     //设置画笔。采用系统预定定义的黑色画笔
     hPen=(HPEN)GetStockObject(BLACK_PEN);
     //定义画刷，采用系统预定义的深灰色画刷
     hBrush=(HBRUSH)GetStockObject(DKGRAY_BRUSH);
     SelectObject(hDC,hBrush); //选择画刷
     SelectObject(hDC,hPen); //选择画笔
     RoundRect(hDC,50,120,100,200,15,15); //圆角矩形
     //定义画刷，采用系统预定义的亮灰色画刷
     hBrush=(HBRUSH)GetStockObject(LTGRAY_BRUSH);
     SelectObject(hDC,hBrush); //选择画刷
     Ellipse(hDC,150,50,200,150); //椭圆
     //定义画刷，采用系统预定义的虚画刷
     hBrush=(HBRUSH)GetStockObject(HOLLOW_BRUSH);
     SelectObject(hDC,hBrush); //选择画刷
     Pie(hDC,250,50,300,100,250,50,300,50); //饼形
     EndPaint(hwndDlg,&PtStr); //结束绘图
     return TRUE;
    case WM_INITDIALOG:
      return TRUE;
    case WM_CLOSE:
     EndDialog(hwndDlg, 0);
     return TRUE;
  }
  return FALSE;
}
int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd)
{
  hInst = hInstance;
  // The user interface is a modal dialog box
  return DialogBox(hInstance, MAKEINTRESOURCE(DLG_MAIN), NULL, (DLGPROC)DialogProc);
}