宁静致远

打印质数

blog of vc_student — Fri, 30 Nov 2007 07:28:00 GMT

/*
* 这就是“亚里士多德筛子” ？
* Created by SharpDevelop.
* Author: student
* Date: 2007-11-30
* Time: 12:03
*
* dashan2046@qq.com
*/

using System;
using System.Collections;

class Prime
{
private ArrayList PrimeList = new ArrayList();
private int EndNum;
public Prime(int EndNum)
{
  this.EndNum = EndNum;
  for(int i = 0; i < EndNum; i++)
  {
   PrimeList.Add(i);
  }

  for(int j = 2; j < EndNum; j++)
  {
   for(int k = j+1; k < EndNum; k++)
   {
    if((int)PrimeList[k] != 0 && ((int)PrimeList[k])%j == 0)
     PrimeList[k] = 0;
   }
  }
}
public void PrintPrime()
{
  int l = 0;
  for(int i = 0; i < PrimeList.Count; i++)
  {
   if((int)PrimeList[i] != 0)
   {
    Console.Write("{0,-10}",PrimeList[i]);
    l++;
    if(l%10 == 0)
     Console.WriteLine();
   }
  }
}
}
class printPrime
{
static void Main()
{
  Prime p = new Prime(10000);
  p.PrintPrime();
}
}

/*
1         2         3         5         7         11        13        17        19        23
29        31        37        41        43        47        53        59        61        67
71        73        79        83        89        97        101       103       107       109
113       127       131       137       139       149       151       157       163       167
173       179       181       191       193       197       199       211       223       227
229       233       239       241       251       257       263       269       271       277
281       283       293       307       311       313       317       331       337       347
349       353       359       367       373       379       383       389       397       401
409       419       421       431       433       439       443       449       457       461
463       467       479       487       491       499       503       509       521       523
541       547       557       563       569       571       577       587       593       599
601       607       613       617       619       631       641       643       647       653
659       661       673       677       683       691       701       709       719       727
733       739       743       751       757       761       769       773       787       797
809       811       821       823       827       829       839       853       857       859
863       877       881       883       887       907       911       919       929       937
941       947       953       967       971       977       983       991       997       1009
1013      1019      1021      1031      1033      1039      1049      1051      1061      1063
1069      1087      1091      1093      1097      1103      1109      1117      1123      1129
1151      1153      1163      1171      1181      1187      1193      1201      1213      1217
1223      1229      1231      1237      1249      1259      1277      1279      1283      1289
1291      1297      1301      1303      1307      1319      1321      1327      1361      1367
1373      1381      1399      1409      1423      1427      1429      1433      1439      1447
1451      1453      1459      1471      1481      1483      1487      1489      1493      1499
1511      1523      1531      1543      1549      1553      1559      1567      1571      1579
1583      1597      1601      1607      1609      1613      1619      1621      1627      1637
1657      1663      1667      1669      1693      1697      1699      1709      1721      1723
1733      1741      1747      1753      1759      1777      1783      1787      1789      1801
1811      1823      1831      1847      1861      1867      1871      1873      1877      1879
1889      1901      1907      1913      1931      1933      1949      1951      1973      1979
1987      1993      1997      1999      2003      2011      2017      2027      2029      2039
2053      2063      2069      2081      2083      2087      2089      2099      2111      2113
2129      2131      2137      2141      2143      2153      2161      2179      2203      2207
2213      2221      2237      2239      2243      2251      2267      2269      2273      2281
2287      2293      2297      2309      2311      2333      2339      2341      2347      2351
2357      2371      2377      2381      2383      2389      2393      2399      2411      2417
2423      2437      2441      2447      2459      2467      2473      2477      2503      2521
2531      2539      2543      2549      2551      2557      2579      2591      2593      2609
2617      2621      2633      2647      2657      2659      2663      2671      2677      2683
2687      2689      2693      2699      2707      2711      2713      2719      2729      2731
2741      2749      2753      2767      2777      2789      2791      2797      2801      2803
2819      2833      2837      2843      2851      2857      2861      2879      2887      2897
2903      2909      2917      2927      2939      2953      2957      2963      2969      2971
2999      3001      3011      3019      3023      3037      3041      3049      3061      3067
3079      3083      3089      3109      3119      3121      3137      3163      3167      3169
3181      3187      3191      3203      3209      3217      3221      3229      3251      3253
3257      3259      3271      3299      3301      3307      3313      3319      3323      3329
3331      3343      3347      3359      3361      3371      3373      3389      3391      3407
3413      3433      3449      3457      3461      3463      3467      3469      3491      3499
3511      3517      3527      3529      3533      3539      3541      3547      3557      3559
3571      3581      3583      3593      3607      3613      3617      3623      3631      3637
3643      3659      3671      3673      3677      3691      3697      3701      3709      3719
3727      3733      3739      3761      3767      3769      3779      3793      3797      3803
3821      3823      3833      3847      3851      3853      3863      3877      3881      3889
3907      3911      3917      3919      3923      3929      3931      3943      3947      3967
3989      4001      4003      4007      4013      4019      4021      4027      4049      4051
4057      4073      4079      4091      4093      4099      4111      4127      4129      4133
4139      4153      4157      4159      4177      4201      4211      4217      4219      4229
4231      4241      4243      4253      4259      4261      4271      4273      4283      4289
4297      4327      4337      4339      4349      4357      4363      4373      4391      4397
4409      4421      4423      4441      4447      4451      4457      4463      4481      4483
4493      4507      4513      4517      4519      4523      4547      4549      4561      4567
4583      4591      4597      4603      4621      4637      4639      4643      4649      4651
4657      4663      4673      4679      4691      4703      4721      4723      4729      4733
4751      4759      4783      4787      4789      4793      4799      4801      4813      4817
4831      4861      4871      4877      4889      4903      4909      4919      4931      4933
4937      4943      4951      4957      4967      4969      4973      4987      4993      4999
5003      5009      5011      5021      5023      5039      5051      5059      5077      5081
5087      5099      5101      5107      5113      5119      5147      5153      5167      5171
5179      5189      5197      5209      5227      5231      5233      5237      5261      5273
5279      5281      5297      5303      5309      5323      5333      5347      5351      5381
5387      5393      5399      5407      5413      5417      5419      5431      5437      5441
5443      5449      5471      5477      5479      5483      5501      5503      5507      5519
5521      5527      5531      5557      5563      5569      5573      5581      5591      5623
5639      5641      5647      5651      5653      5657      5659      5669      5683      5689
5693      5701      5711      5717      5737      5741      5743      5749      5779      5783
5791      5801      5807      5813      5821      5827      5839      5843      5849      5851
5857      5861      5867      5869      5879      5881      5897      5903      5923      5927
5939      5953      5981      5987      6007      6011      6029      6037      6043      6047
6053      6067      6073      6079      6089      6091      6101      6113      6121      6131
6133      6143      6151      6163      6173      6197      6199      6203      6211      6217
6221      6229      6247      6257      6263      6269      6271      6277      6287      6299
6301      6311      6317      6323      6329      6337      6343      6353      6359      6361
6367      6373      6379      6389      6397      6421      6427      6449      6451      6469
6473      6481      6491      6521      6529      6547      6551      6553      6563      6569
6571      6577      6581      6599      6607      6619      6637      6653      6659      6661
6673      6679      6689      6691      6701      6703      6709      6719      6733      6737
6761      6763      6779      6781      6791      6793      6803      6823      6827      6829
6833      6841      6857      6863      6869      6871      6883      6899      6907      6911
6917      6947      6949      6959      6961      6967      6971      6977      6983      6991
6997      7001      7013      7019      7027      7039      7043      7057      7069      7079
7103      7109      7121      7127      7129      7151      7159      7177      7187      7193
7207      7211      7213      7219      7229      7237      7243      7247      7253      7283
7297      7307      7309      7321      7331      7333      7349      7351      7369      7393
7411      7417      7433      7451      7457      7459      7477      7481      7487      7489
7499      7507      7517      7523      7529      7537      7541      7547      7549      7559
7561      7573      7577      7583      7589      7591      7603      7607      7621      7639
7643      7649      7669      7673      7681      7687      7691      7699      7703      7717
7723      7727      7741      7753      7757      7759      7789      7793      7817      7823
7829      7841      7853      7867      7873      7877      7879      7883      7901      7907
7919      7927      7933      7937      7949      7951      7963      7993      8009      8011
8017      8039      8053      8059      8069      8081      8087      8089      8093      8101
8111      8117      8123      8147      8161      8167      8171      8179      8191      8209
8219      8221      8231      8233      8237      8243      8263      8269      8273      8287
8291      8293      8297      8311      8317      8329      8353      8363      8369      8377
8387      8389      8419      8423      8429      8431      8443      8447      8461      8467
8501      8513      8521      8527      8537      8539      8543      8563      8573      8581
8597      8599      8609      8623      8627      8629      8641      8647      8663      8669
8677      8681      8689      8693      8699      8707      8713      8719      8731      8737
8741      8747      8753      8761      8779      8783      8803      8807      8819      8821
8831      8837      8839      8849      8861      8863      8867      8887      8893      8923
8929      8933      8941      8951      8963      8969      8971      8999      9001      9007
9011      9013      9029      9041      9043      9049      9059      9067      9091      9103
9109      9127      9133      9137      9151      9157      9161      9173      9181      9187
9199      9203      9209      9221      9227      9239      9241      9257      9277      9281
9283      9293      9311      9319      9323      9337      9341      9343      9349      9371
9377      9391      9397      9403      9413      9419      9421      9431      9433      9437
9439      9461      9463      9467      9473      9479      9491      9497      9511      9521
9533      9539      9547      9551      9587      9601      9613      9619      9623      9629
9631      9643      9649      9661      9677      9679      9689      9697      9719      9721
9733      9739      9743      9749      9767      9769      9781      9787      9791      9803
9811      9817      9829      9833      9839      9851      9857      9859      9871      9883
9887      9901      9907      9923      9929      9931      9941      9949      9967      9973

*/

我会发线程消息了

blog of vc_student — Tue, 06 Nov 2007 08:34:00 GMT

GetMessage()从调用线程的消息队列中取消息，如果队列空就阻塞。

代码如下：

DWORD __stdcall PostMess(LPVOID lp);

void CTMsgDlg::OnBnClickedButton1()
{
// TODO: 在此添加控件通知处理程序代码
hThreadPM= CreateThread(NULL, 0, PostMess, NULL, 0, &dwThreadId);

}

void CTMsgDlg::OnBnClickedButton2()
{
// TODO: 在此添加控件通知处理程序代码
PostThreadMessage(dwThreadId,8888,0,0);
}

MSG message;

DWORD __stdcall PostMess(LPVOID lp)
{

    while(::GetMessage(&message, NULL, 0, 0))
    {
        ::TranslateMessage(&message);
        ::DispatchMessage(&message);
        switch(message.message)
        {
        case 8888:
   ::Beep(100,100);
            break;
  }
}
return 0;

}

在派生类中重载基类的成员函数

blog of vc_student — Tue, 02 Oct 2007 13:40:00 GMT

例：
class base
{
public:
    void fun(int param);
    void fun(char param);
};

class derive :public base
{
public:
    void fun(string param);
    using base:fun; //只能用函数名，不能带参数，表示引入基类的重载函数集，而不能是一个实例
};

收集VC错误

blog of vc_student — Thu, 27 Sep 2007 14:44:00 GMT

1.
nafxcwd.lib(appcore.obj) : error LNK2001: unresolved external symbol ___argv
nafxcwd.lib(appcore.obj) : error LNK2001: unresolved external symbol ___argc
nafxcwd.lib(timecore.obj) : error LNK2001: unresolved external symbol __mbctype
nafxcwd.lib(apphelp.obj) : error LNK2001: unresolved external symbol __mbctype
nafxcwd.lib(filelist.obj) : error LNK2001: unresolved external symbol __mbctype
解决办法：
PROJECT->SETING->C/C++->PREPROCESSOR->定义 _AFXDLL,完毕。
2.
LINK : warning LNK4098: defaultlib "MSVCRT" conflicts with use of other libs; use /NODEFAULTLIB:library
解决办法：
PROJECT->SETING->LINK->INPUT->IGNORE LIB...->MSVCRT.LIB

输出结果为什么是这样？

blog of vc_student — Fri, 07 Sep 2007 14:55:00 GMT

#include "stdafx.h"
#include <map>
#include <iostream>
#include <string>
#include <vector>
#include <set>

using namespace std;

int main(int argc, char* argv[])
{
set<string> set_str;
set_str.insert("one");
set_str.insert("tow");
set_str.insert("three");

set<string>::iterator it = set_str.begin();
while(it != set_str.end())
{
cout<<*it<<endl;
it++;
}

return 0;
}

/*
输出结果为什么是：
one
three
tow
Press any key to continue
*/

生成随机数测试代码

blog of vc_student — Tue, 21 Aug 2007 15:12:00 GMT

// Rand.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <stdlib.h>
#include <stdio.h>
#include <time.h>

int main(int argc, char* argv[])
{
int i,j;

srand( (unsigned)time( NULL ) );
int total[2] = {0};
int temp = 0;

for( i = 0;   i < 1000000;i++ )
{
  temp = rand()%2;
  printf( " %d\n",temp);
  total[temp]++;
}

printf("############################################################################\n");

for(j = 0; j < 2; j++)
{
printf("total[%d]=%d\n",j,total[j]);
}

system("pause");

return 0;
}

/*
结果：

第一组：
total[0]=500026
total[1]=499974
第二组：
total[0]=500159
total[1]=499841
第三组：
total[0]=500023
total[1]=499977
第四组：
total[0]=500034
total[1]=499966
第五组：
total[0]=499962
total[1]=500038
第六组：
total[0]=499898
total[1]=500102
第七组：
total[0]=500002
total[1]=499998
第八组：
total[0]=499991
total[1]=500009
第九组：
total[0]=500106
total[1]=499894
第十组：
total[0]=499997
total[1]=500003
*/

取得网卡信息（转）

blog of vc_student — Sun, 12 Aug 2007 12:56:00 GMT

//使用ATL
#pragma once

#include "atlstr.h"
#include "iphlpapi.h"
#pragma comment(lib,"iphlpapi.lib")

class CDnpNetworkInterface
{
_MIB_IFTABLE* _pInfoBuffer;

protected:

bool GetNicInformation(void)
{
DWORD ret;
ULONG dwSize;

  dwSize = 0;
  ret = ::GetIfTable(NULL,&dwSize,TRUE);
  if(ret != NO_ERROR && ret != ERROR_INSUFFICIENT_BUFFER)
   return false;

if(_pInfoBuffer)
delete (BYTE*)_pInfoBuffer;

  _pInfoBuffer = (_MIB_IFTABLE*)new BYTE[dwSize];
  if(_pInfoBuffer == NULL)
   return false;

  ZeroMemory(_pInfoBuffer,dwSize);
  ret = ::GetIfTable(_pInfoBuffer,&dwSize,TRUE);
  if(ret != NO_ERROR)
  {
   delete (BYTE*)_pInfoBuffer;
   _pInfoBuffer = NULL;
   return false;
  }

return true;
}

bool IsValidInfo(void)
{
if(_pInfoBuffer)
return true;

return GetNicInformation();
}

public:

CDnpNetworkInterface()
{
_pInfoBuffer = NULL;
}

~CDnpNetworkInterface()
{
if(_pInfoBuffer)
delete (BYTE*)_pInfoBuffer;
}

DWORD GetNicCount(void)
{
if(IsValidInfo() == false)
return 0;

return _pInfoBuffer->dwNumEntries;
}

bool GetNicName(DWORD dwIndex,CAtlString* pstrName)
{
  if(pstrName == NULL)
   return false;
  *pstrName = _T("");
  if(dwIndex >= GetNicCount())
   return false;

*pstrName = (char*)_pInfoBuffer->table[dwIndex].bDescr;

return true;
}

bool GetNicMacAddress(DWORD dwIndex,CAtlString* pstrMacAddress,int nFormat=0)
{
  if(pstrMacAddress == NULL)
   return false;
  *pstrMacAddress = _T("");
  if(dwIndex >= GetNicCount())
   return false;

  switch(nFormat)
  {
  case 1:
   pstrMacAddress->Format(_T("%02X %02X %02X %02X %02X %02X")
     ,_pInfoBuffer->table[dwIndex].bPhysAddr[0]
     ,_pInfoBuffer->table[dwIndex].bPhysAddr[1]
     ,_pInfoBuffer->table[dwIndex].bPhysAddr[2]
     ,_pInfoBuffer->table[dwIndex].bPhysAddr[3]
     ,_pInfoBuffer->table[dwIndex].bPhysAddr[4]
     ,_pInfoBuffer->table[dwIndex].bPhysAddr[5]);
   break;

  case 2:
   pstrMacAddress->Format(_T("%02X%02X%02X%02X%02X%02X")
     ,_pInfoBuffer->table[dwIndex].bPhysAddr[0]
     ,_pInfoBuffer->table[dwIndex].bPhysAddr[1]
     ,_pInfoBuffer->table[dwIndex].bPhysAddr[2]
     ,_pInfoBuffer->table[dwIndex].bPhysAddr[3]
     ,_pInfoBuffer->table[dwIndex].bPhysAddr[4]
     ,_pInfoBuffer->table[dwIndex].bPhysAddr[5]);
   break;

  case 0:
  default:
   pstrMacAddress->Format(_T("%02X-%02X-%02X-%02X-%02X-%02X")
     ,_pInfoBuffer->table[dwIndex].bPhysAddr[0]
     ,_pInfoBuffer->table[dwIndex].bPhysAddr[1]
     ,_pInfoBuffer->table[dwIndex].bPhysAddr[2]
     ,_pInfoBuffer->table[dwIndex].bPhysAddr[3]
     ,_pInfoBuffer->table[dwIndex].bPhysAddr[4]
     ,_pInfoBuffer->table[dwIndex].bPhysAddr[5]);
   break;
  }

return true;
}

DWORD GetNicConnectionSpeed(DWORD dwIndex)
{
if(dwIndex >= GetNicCount())
return 0;

return _pInfoBuffer->table[dwIndex].dwSpeed;
}

bool IsNicWorking(DWORD dwIndex)
{
if(dwIndex >= GetNicCount())
return false;

return (_pInfoBuffer->table[dwIndex].dwOperStatus == MIB_IF_OPER_STATUS_OPERATIONAL) ? true : false;
}

};

//使用方法
void Test(void)
{
bool  ret;
DWORD  i;
DWORD  dwSize;
DWORD  dwSpeed;
CAtlString strName;
CAtlString strMacAddress;
CAtlString strBuff;
CAtlString strMessage;
CDnpNetworkInterface cDevice;

dwSize = cDevice.GetNicCount();
for(i = 0; i < dwSize; i++)
{
  ret = cDevice.GetNicName(i,&strName);
  if(ret == false)
   continue;

  ret = cDevice.GetNicMacAddress(i,&strMacAddress);
  if(ret == false)
   continue;

dwSpeed = cDevice.GetNicConnectionSpeed(i);

  strBuff.Format(_T("描述：%s\nMAC地址：%s\n连接速度：%dKbps\n"),strName,strMacAddress,dwSpeed/1000);
  strMessage += strBuff;
  if(cDevice.IsNicWorking(i))
   strMessage += _T("工作：正常\n");
  else
   strMessage += _T("工作：停止中\n");

strMessage += _T("\n");
}

::MessageBox(NULL,strMessage,_T(""),MB_OK);
}

Overlapped I/O

blog of vc_student — Wed, 08 Aug 2007 13:58:00 GMT

<PRE lang=c++>OVERLAPPED op;
HANDLE      h,
            handleArray[2];
BOOL        bStop = FALSE;

memset(&op, 0, sizeof(op));
handleArray[0] = op.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
handleArray[1] = gbl_hStopEvent;

while (bStop == FALSE)
{
    h = CreateNamedPipe(FILE_FLAG_OVERLAPPED);

    ConnectNamedPipe(h, &op);

    switch (WaitForMultipleObjects(2, handleArray, FALSE, INFINITE))
    {
    case WAIT_OBJECT_0:
        _beginthread(threadProc, 0, h);
        ResetEvent(handleArray[0]);
        break;

    case WAIT_OBJECT_0 + 1:
        CloseHandle(h);
        bStop = TRUE;
        break;
    }
}

CloseHandle(handleArray[0]);
</PRE>

MS挺周到的

blog of vc_student — Wed, 18 Jul 2007 02:06:00 GMT

1.使用微软的FCI/FDI库进行文件压缩;
2.可以使用微软的加解密库；
......

没事写的一个arp欺骗监测工具

blog of vc_student — Sun, 29 Apr 2007 09:19:00 GMT

http://blog.vckbase.com/Files/star/ArpMonitor.rar

谁有空帮测一下？别笑我呀，软件太不完善！

wspiapi.h(45) : error C2265.....解决办法

blog of vc_student — Sun, 28 May 2006 09:11:00 GMT

在win2000平台，win2003sp1 SDK下的编译错误,解决办法是在include wspiapi.h之前#define _WSPIAPI_COUNTOF

c:\program files\microsoft platform sdk\include\wspiapi.h(45) : error C2265: '<Unknown>' : reference to a zero-sized array is illegal
c:\program files\microsoft platform sdk\include\wspiapi.h(45) : error C2265: '<Unknown>' : reference to a zero-sized array is illegal

可以这样监视系统性能参数

blog of vc_student — Thu, 18 May 2006 08:20:00 GMT

搜集网友的DES加解密代码，看了之后西里图胡！！！

blog of vc_student — Thu, 11 May 2006 02:35:00 GMT

代码先放到这，希望有兴趣的朋友测试和交流！
http://blog.vckbase.com/Files/star/DES.rar

illustrates the basic debugging features

blog of vc_student — Thu, 01 Dec 2005 07:06:00 GMT

/*****************************************************************
*       ?000 Microsoft Corporation                  *
* CRT_DBG1                                                     *
* This simple program illustrates the basic debugging features *
* of the C runtime libraries, and the kind of debug output     *
* that these features generate.                                *
*****************************************************************/

#include <stdio.h>
#include <string.h>
#include <malloc.h>
#include <crtdbg.h>

// This routine place comments at the head of a section of debug output
void OutputHeading( const char * explanation )
{
_RPT1( _CRT_WARN, "\n\n%s:\n**************************************\
************************************\n", explanation );
}

// The following macros set and clear, respectively, given bits
// of the C runtime library debug flag, as specified by a bitmask.
#ifdef   _DEBUG
#define SET_CRT_DEBUG_FIELD(a) \
            _CrtSetDbgFlag((a) | _CrtSetDbgFlag(_CRTDBG_REPORT_FLAG))
#define CLEAR_CRT_DEBUG_FIELD(a) \
            _CrtSetDbgFlag(~(a) & _CrtSetDbgFlag(_CRTDBG_REPORT_FLAG))
#else
#define SET_CRT_DEBUG_FIELD(a)   ((void) 0)
#define CLEAR_CRT_DEBUG_FIELD(a) ((void) 0)
#endif

int main( )
{
char *p1, *p2;
#ifdef _DEBUG
_CrtMemState s1, s2, s3;
#endif

#ifndef _DEBUG
printf("Skipping this for non-debug mode.\n");
return 2;
#endif

   // Send all reports to STDOUT
   _CrtSetReportMode( _CRT_WARN, _CRTDBG_MODE_FILE );
   _CrtSetReportFile( _CRT_WARN, _CRTDBG_FILE_STDOUT );
   _CrtSetReportMode( _CRT_ERROR, _CRTDBG_MODE_FILE );
   _CrtSetReportFile( _CRT_ERROR, _CRTDBG_FILE_STDOUT );
   _CrtSetReportMode( _CRT_ASSERT, _CRTDBG_MODE_FILE );
   _CrtSetReportFile( _CRT_ASSERT, _CRTDBG_FILE_STDOUT );

   // Allocate 2 memory blocks and store a string in each
   p1 = malloc( 34 );
   strcpy( p1, "This is the p1 string (34 bytes)." );

p2 = malloc( 34 );
strcpy( p2, "This is the p2 string (34 bytes)." );

   OutputHeading(
      "Use _ASSERTE to check that the two strings are identical" );
   _ASSERTE( strcmp( p1, p2 ) == 0 );

   OutputHeading(
      "Use a _RPT macro to report the string contents as a warning" );
   _RPT2( _CRT_WARN, "p1 points to '%s' and \np2 points to '%s'\n", p1, p2 );

   OutputHeading(
      "Use _CRTMemDumpAllObjectsSince to check the p1 and p2 allocations" );
   _CrtMemDumpAllObjectsSince( NULL );

free( p2 );

   OutputHeading(
      "Having freed p2, dump allocation information about p1 only" );
   _CrtMemDumpAllObjectsSince( NULL );

// Store a memory checkpoint in the s1 memory-state structure
_CrtMemCheckpoint( &s1 );

   // Allocate another block, pointed to by p2
   p2 = malloc( 38 );
   strcpy( p2, "This new p2 string occupies 38 bytes.");

// Store a 2nd memory checkpoint in s2
_CrtMemCheckpoint( &s2 );

   OutputHeading(
      "Dump the changes that occurred between two memory checkpoints" );
   if ( _CrtMemDifference( &s3, &s1, &s2 ) )
      _CrtMemDumpStatistics( &s3 );

   // Free p2 again and store a new memory checkpoint in s2
   free( p2 );
   _CrtMemCheckpoint( &s2 );

   OutputHeading(
      "Now the memory state at the two checkpoints is the same" );
   if ( _CrtMemDifference( &s3, &s1, &s2 ) )
      _CrtMemDumpStatistics( &s3 );

   strcpy( p1, "This new p1 string is over 34 bytes" );
   OutputHeading( "Free p1 after overwriting the end of the allocation" );
   free( p1 );

   // Set the debug-heap flag so that freed blocks are kept on the
   // linked list, to catch any inadvertent use of freed memory
   SET_CRT_DEBUG_FIELD( _CRTDBG_DELAY_FREE_MEM_DF );

   p1 = malloc( 10 );
   free( p1 );
   strcpy( p1, "Oops" );

OutputHeading( "Perform a memory check after corrupting freed memory" );
_CrtCheckMemory( );

   // Use explicit calls to _malloc_dbg to save file name and line number
   // information, and also to allocate Client type blocks for tracking
   p1 = _malloc_dbg( 40, _NORMAL_BLOCK, __FILE__, __LINE__ );
   p2 = _malloc_dbg( 40, _CLIENT_BLOCK, __FILE__, __LINE__ );
   strcpy( p1, "p1 points to a Normal allocation block" );
   strcpy( p2, "p2 points to a Client allocation block" );

   // You must use _free_dbg to free a Client block
   OutputHeading(
      "Using free( ) to free a Client block causes an assertion failure" );
   free( p1 );
   free( p2 );

   p1 = malloc( 10 );
   OutputHeading( "Examine outstanding allocations (dump memory leaks)" );
   _CrtDumpMemoryLeaks( );

   // Set the debug-heap flag so that memory leaks are reported when
   // the process terminates. Then, exit.
   OutputHeading( "Program exits without freeing a memory block" );
   SET_CRT_DEBUG_FIELD( _CRTDBG_LEAK_CHECK_DF );

system("pause");
}