C++ - 判断文件夹(folder)是否存在(exist)

判断文件夹(folder)是否存在(exit)

本文地址: http://blog.csdn.net/caroline_wendy/article/details/21734915

写入程序, 需要在文件夹中写入数据, 如果文件夹不存在, 则无法写入, 在程序入口需要判断;

由于属于系统层, Windows的两种解决方法.

参考: http://stackoverflow.com/questions/8233842/how-to-check-if-directory-exist-using-c-and-winapi

1. GetFileAttributesA()函数
DWORD d = GetFileAttributesA(const char* filename); #include <windows.h>
windows系统函数, 判断文件夹是否存在;
代码:

#include <iostream>
#include <string>
 
#include <windows.h>
 
using namespace std;
 
bool dirExists(const std::string& dirName_in)
{
    DWORD ftyp = GetFileAttributesA(dirName_in.c_str());
    if (ftyp == INVALID_FILE_ATTRIBUTES)
        return false;  //something is wrong with your path!
 
    if (ftyp & FILE_ATTRIBUTE_DIRECTORY)
        return true;   // this is a directory!
 
    return false;    // this is not a directory!
}
 
int main(void) 
{
    std::string folder("./Test");
 
    if (dirExists(folder)) {
        std::cout << "Folder : " << folder << " exist!" << std::endl;
    } else {
        std::cout << "Folder : " << folder << " doesn't exist!" << std::endl;
    }
 
    std::string nofolder("./TestNo");
 
    if (dirExists(nofolder)) {
        std::cout << "Folder : " << nofolder << " exist!" << std::endl;
    } else {
        std::cout << "Folder : " << nofolder << " doesn't exist!" << std::endl;
    }
 
    return 0;
}

2. _access()函数
int access(const char *filename, int mode); #include <io.h>

mode设为0, 判断文件是否存在; 返回0, 文件存在;

代码:

#include <iostream>
#include <string>
 
#include <io.h>
 
using namespace std;
 
bool dirExists(const std::string& dirName_in)
{
    int ftyp = _access(dirName_in.c_str(), 0);
 
    if (0 == ftyp)
        return true;   // this is a directory!
    else 
        return false;    // this is not a directory!
}
 
int main(void) 
{
    std::string folder("./Test");
 
    if (dirExists(folder)) {
        std::cout << "Folder : " << folder << " exist!" << std::endl;
    } else {
        std::cout << "Folder : " << folder << " doesn't exist!" << std::endl;
    }
 
    std::string nofolder("./TestNo");
 
    if (dirExists(nofolder)) {
        std::cout << "Folder : " << nofolder << " exist!" << std::endl;
    } else {
        std::cout << "Folder : " << nofolder << " doesn't exist!" << std::endl;
    }
 
    return 0;
}

--------------------- 
作者：SpikeKing 
来源：CSDN 
原文：https://blog.csdn.net/caroline_wendy/article/details/21734915 
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