[C++知识库]C++超好用的函数

获取IP地址：

const char* GetLocalIpAddress()
{
	WORD wVersionRequested = MAKEWORD(2, 2);

	WSADATA wsaData;
	if (WSAStartup(wVersionRequested, &wsaData) != 0)
		return "-1";

	char local[255] = { 0 };
	gethostname(local, sizeof(local));
	hostent* ph = gethostbyname(local);
	if (ph == NULL)
		return "-1";

	in_addr addr;
	memcpy(&addr, ph->h_addr_list[0], sizeof(in_addr)); //这里仅获取第一个ip

	char* localIP;
	localIP = inet_ntoa(addr);

	WSACleanup();
	return localIP;
}

截屏（全屏）：

void Cutscreen(char* fileName)
{
	HWND window = GetDesktopWindow();
	HDC _dc = GetWindowDC(window);
	HDC dc = CreateCompatibleDC(0);

	RECT re;
	GetWindowRect(window, &re);
	int w = re.right,
		h = re.bottom;
	void* buf = new char[w * h * 4];

	HBITMAP bm = CreateCompatibleBitmap(_dc, w, h);
	SelectObject(dc, bm);

	StretchBlt(dc, 0, 0, w, h, _dc, 0, 0, w, h, SRCCOPY);

	void* f = CreateFile(fileName, GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, 0, 0);

	GetObject(bm, 84, buf);

	tagBITMAPINFO bi;
	bi.bmiHeader.biSize = sizeof(bi.bmiHeader);
	bi.bmiHeader.biWidth = w;
	bi.bmiHeader.biHeight = h;
	bi.bmiHeader.biPlanes = 1;
	bi.bmiHeader.biBitCount = 32;
	bi.bmiHeader.biCompression = 0;
	bi.bmiHeader.biSizeImage = 0;

	CreateDIBSection(dc, &bi, DIB_RGB_COLORS, &buf, 0, 0);
	GetDIBits(dc, bm, 0, h, buf, &bi, DIB_RGB_COLORS);

	BITMAPFILEHEADER bif;
	bif.bfType = MAKEWORD('B', 'M');
	bif.bfSize = w * h * 4 + 54;
	bif.bfOffBits = 54;

	BITMAPINFOHEADER bii;
	bii.biSize = 40;
	bii.biWidth = w;
	bii.biHeight = h;
	bii.biPlanes = 1;
	bii.biBitCount = 32;
	bii.biCompression = 0;
	bii.biSizeImage = w * h * 4;

	DWORD r;
	WriteFile(f, &bif, sizeof(bif), &r, NULL);
	WriteFile(f, &bii, sizeof(bii), &r, NULL);
	WriteFile(f, buf, w * h * 4, &r, NULL);

	CloseHandle(f);
	DeleteDC(_dc);
	DeleteDC(dc);
}

检测IP正确性：

inline bool ChickIpAddress(const char* pszIPAddr)
{
	if (!pszIPAddr) return false; //若pszIPAddr为空  
	char IP1[128], cIP[4];
	int len = strlen(pszIPAddr);
	int i = 0, j = len - 1;
	int k, m = 0, n = 0, num = 0;
	//去除首尾空格(取出从i-1到j+1之间的字符):  
	while (pszIPAddr[i++] == ' ');
	while (pszIPAddr[j--] == ' ');

	for (k = i - 1; k <= j + 1; k++)
	{
		IP1[m++] = pszIPAddr[k];
	}
	IP1[m] = '\0';

	char* p = IP1;

	while (*p != '\0')
	{
		if (*p == ' ' || *p < '0' || *p > '9') return false;
		cIP[n++] = *p; //保存每个子段的第一个字符，用于之后判断该子段是否为0开头  

		int sum = 0;  //sum为每一子段的数值，应在0到255之间  
		while (*p != '.' && *p != '\0')
		{
			if (*p == ' ' || *p < '0' || *p > '9') return false;
			sum = sum * 10 + *p - 48;  //每一子段字符串转化为整数  
			p++;
		}
		if (*p == '.') {
			if ((*(p - 1) >= '0' && *(p - 1) <= '9') && (*(p + 1) >= '0' && *(p + 1) <= '9'))//判断"."前后是否有数字，若无，则为无效IP，如“1.1.127.”  
				num++;  //记录“.”出现的次数，不能大于3  
			else
				return false;
		};
		if ((sum > 255) || (sum > 0 && cIP[0] == '0') || num > 3) return false;//若子段的值>255或为0开头的非0子段或“.”的数目>3，则为无效IP  

		if (*p != '\0') p++;
		n = 0;
	}
	if (num != 3) return false;
	return true;
}

打开exe文件：

BOOL OpenExeFile(LPCSTR mode, LPCSTR filename)
{
	SHELLEXECUTEINFO shell = { sizeof(shell) };
	shell.fMask = SEE_MASK_FLAG_DDEWAIT;
	shell.lpVerb = mode;//模式，一般为open
	shell.lpFile = filename;//文件名
	shell.nShow = SW_SHOWNORMAL;//显示
	BOOL ret = ShellExecuteEx(&shell);//return ShellExecuteEx(&shell);
	return ret;
}