向此代码添加NULL [英] Adding NULL To This Code

问题描述

此函数返回目录中的文件计数......但是，如果文件不存在，该函数将中断.我如何在其中添加NULL以不覆盖所需类型的文件.如果找不到文件，我希望它返回0.

This function is returning a count of files in the directory.....However If the file doesn''t exsist the function breaks. How can I add NULL to this to cover no files of the type desired. I want it to return 0 if no files are found.

int count = GetFileList(L"C:\\Users\\DS\\Downloads\\*.pdf", map);

函数本身.

The function itself.

int GetFileList(const wchar_t *searchkey, std::map &map)

抱歉，这是整个代码.

My apologies, here is the entire code.

struct file_data 
{ 
    std::wstring sLastAccessTime; 
    __int64 nFileSize      ; 
};
  
int GetFileList(const wchar_t *searchkey, std::map &map) 
{ 
    WIN32_FIND_DATA fd; 
    HANDLE h = FindFirstFile(searchkey,&fd); 
    if(h == INVALID_HANDLE_VALUE) 
    { 
        return 0; // no files found 
    } 
    while(1) 
    { 
       	wchar_t buf[128]; 
        FILETIME ft = fd.ftLastWriteTime; 
        SYSTEMTIME sysTime; 
        FileTimeToSystemTime(&ft, &sysTime); 
        wsprintf(buf, L"%d-%02d-%02d",sysTime.wYear, sysTime.wMonth, sysTime.wDay); 
		
	file_data filedata; 
        filedata.sLastAccessTime= buf; 
        filedata.nFileSize      = (((__int64)fd.nFileSizeHigh) << 32) + fd.nFileSizeLow; 
 
        map[fd.cFileName]= filedata; 
 
        if (FindNextFile(h, &fd) == FALSE) 
            break; 
    } 
    return map.size(); 
} 
 
int main() 
{ 
#define NULL 0;
	std::map map; 
        int count = GetFileList(L"C:\\Users\\DS\\Downloads\\*.pdf", map);
	int count1 = GetFileList(L"C:\\Users\\DS\\Downloads\\*.txt", map);
	int count2 = GetFileList(L"C:\\Users\\DS\\Downloads\\*.jpg", map);
	for(std::map::const_iterator it = map.begin(); 
        it != map.end(); ++it) 
    { 
       
		if (count != 0) 
		{ 
		printf("\n   Delete: %i   \n", count);
		} 
		else 
		{ 
		printf ("%s \n", "Nothing");
		
		    } 
	system("pause");
    return 0;
}
}

推荐答案

成员7766180写道:

Member 7766180 wrote:

我希望它如果找不到文件，则返回0.

I want it to return 0 if no files are found.

此代码已经确保没有文件返回时返回0.

This code already ensure 0 is returned when no files are returned.

if(h == INVALID_HANDLE_VALUE) 
{ 
    return 0; // no files found 
} 

在for循环中使用map之前，应更改main()以检查找到的文件数.

试试这个:

You should change your main() to check for the number of found files before using the map in the for loop.

Try this:

GetFileList(L"C:\\Users\\DS\\Downloads\\*.pdf", map);
GetFileList(L"C:\\Users\\DS\\Downloads\\*.txt", map);
GetFileList(L"C:\\Users\\DS\\Downloads\\*.jpg", map);

if( map.size() > 0 )
{
	for(std::map::const_iterator it = map.begin(); it != map.end(); ++it)
	{
		....
	}
}

同样，您还需要在GetFileList函数返回之前关闭查找句柄.
在return map.size();

Also you need to close the find handle before the GetFileList functions returns.
Add FindClose(h); before return map.size();

Er前面添加FindClose(h);，也许您会想编辑问题，以便它实际上包含所讨论的函数，而不是(不完整的)定义呢?只是一个想法...

Er, ahrm - perhaps you''d care to edit the question so that it actually includes the function in question, rather than an (incomplete) definition of it? Just a thought...

这篇关于向此代码添加NULL的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！