C++文件及文件夹操作整理（代码示例）

一 文件

1.1 使用C++标准库中的IO库（fstream）读写文件

1#include <iostream>
2#include <fstream>
3using namespace std;
4
5int main()
6{
7	char szData[200] = "123456 test";
8	fstream fFile;
9	fFile.open("test.txt", ios::app | ios::out | ios::in);
10	/****************将数据写入文件-begin***************/
11	fFile << szData;
12	/****************将数据写入文件-end***************/
13
14	/*************** 将数据从文件中读取出来-begin******************/
15	fFile.seekg(0, ios::end);
16	int iSize = fFile.tellg(); //计算出文件大小
17	fFile.seekg(ios::beg); //从文件最前面开始读取
18	fFile >> noskipws; //设置读取空格、回车
19	std::string strDataOut;
20	for (int i = 0; i < iSize/*!afile.eof()*/; i++)
21	{
22		char c;
23		fFile >> c;
24		strDataOut.push_back(c);
25	}
26
27	cout << strDataOut.c_str();
28	/*************** 将数据从文件中读取出来-end******************/
29	fFile.close();
30	return 0;
31}

1.2 使用windows API读写文件

1#include <windows.h>
2#include <string>
3
4int main()
5{
6	std::string strFileName = "test.txt";
7    /*************************写文件-begin******************************/
8	std::string strData = "123456 test";
9    DWORD dwReturn;
10	HANDLE hFileWrite = CreateFileA(strFileName.c_str(), GENERIC_WRITE,  FILE_SHARE_WRITE, NULL, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
11	if (INVALID_HANDLE_VALUE != hFileWrite)
12	{
13		WriteFile(hFileWrite, strData.c_str(), strData.length(), &dwReturn, NULL);
14		CloseHandle(hFileWrite);
15	}
16	/*************************写文件-end******************************/
17
18	/*************************读文件-begin******************************/
19	DWORD bytesRead = 0;
20	char szBuffer[1024] = { 0 };
21	HANDLE hFileRead = CreateFileA(strFileName.c_str(), GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
22	if (INVALID_HANDLE_VALUE != hFileRead)
23	{
24		ReadFile(hFileRead, szBuffer, 1024/*static_cast<DWORD>(length)*/, &bytesRead, NULL);
25		CloseHandle(hFileRead);
26	}
27	/*************************读文件-end******************************/
28	
29	return 0;
30}

1.3 linux读写文件

1#include <fcntl.h>
2#include <unistd.h>
3#include <string>
4#include <iostream>
5
6int main()
7{
8	std::string strPath = "test.txt";
9	/*************************写文件-begin******************************/
10	int iFileWrite = ::open(strPath.c_str(), O_TRUNC | O_APPEND | O_CREAT | O_RDWR, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);
11	if ( -1 == iFileWrite)
12	{
13		return 0;
14	}
15	std::string strBuffer = "Test Data";
16	int n = write(iFileWrite, strBuffer.c_str(), strBuffer.length());
17	::close(iFileWrite);
18	/*************************写文件-end******************************/
19
20	/*************************读文件-begin******************************/
21	char szBuffer[1024] = { 0 };
22	int iFileRead = ::open(strPath.c_str(), O_RDONLY, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);
23	if (-1 == iFileRead)
24	{
25		return 0;
26	}
27	read(iFileRead, szBuffer, 1024);
28	std::cout << szBuffer;
29	::close(iFileRead);
30	/*************************读文件-end******************************/
31	return 0;
32}

二 文件夹

1.1 Windows

1. 创建文件夹

1#include <direct.h>
2#include <iostream>
3#include <io.h>
4
5using namespace std;
6
7int main()
8{
9	string folderPath = "E:\\Test\\Dir";
10	if (0 != access(folderPath.c_str(), 0))
11	{
12		int iRst = mkdir(folderPath.c_str());   // 需要迭代创建，即创建子文件夹时父文件夹必须存在
13	}
14
15	return 0;
16}

2. 遍历文件夹

1#include "stdafx.h"
2#include <io.h>
3#include <string>
4#include <vector>
5#include <iostream>
6#include <windows.h>
7#include <atlstr.h>
8using namespace std;
9
10//获取文件夹下所有文件名及文件夹总大小
11DWORD TraversalFolder(string strPath, vector<string>& files)
12{
13	DWORD dwRtn = 0;
14	long hFolder = 0;                                     //文件句柄
15	struct _finddata_t fileinfo;                         //文件信息
16	string strFileName = "";
17
18	if ((hFolder = _findfirst(strFileName.assign(strPath).append("\\*").c_str(), &fileinfo)) != -1)
19	{
20		do
21		{
22			DWORD dwSize = 0;
23			//如果是目录,迭代之;如果不是,加入列表
24			if ((fileinfo.attrib &  _A_SUBDIR))
25			{
26				if (strcmp(fileinfo.name, ".") != 0 && strcmp(fileinfo.name, "..") != 0)
27				{
28					dwSize = TraversalFolder(strFileName.assign(strPath).append("\\").append(fileinfo.name), files);
29				}
30			}
31			else
32			{
33				files.push_back(strFileName.assign(strPath).append("\\").append(fileinfo.name));
34				dwSize = fileinfo.size;
35			}
36			dwRtn += dwSize;
37		} while (0 == _findnext(hFolder, &fileinfo));
38
39		_findclose(hFolder);
40	}
41	return dwRtn;
42}
43
44int main()
45{
46	char * filePath = "E:/test";
47	DWORD dwFolderSize;
48	vector<string> files;
49	dwFolderSize = TraversalFolder(filePath, files);//获取文件夹下所有文件名及文件夹总大小
50	system("pause");
51}

1.2 Linux

1. 创建文件夹

1#include <sys/stat.h>
2#include <iostream>
3#include <string>
4
5int main()
6{
7	std::string strParh = "Test111";
8	int isCreate = ::mkdir(strParh.c_str(), S_IRUSR | S_IWUSR | S_IXUSR | S_IRWXG | S_IRWXO);// // 需要迭代创建，即创建子文件夹时父文件夹必须存在
9	if (0 == isCreate)
10	{
11		std::cout << "mkdir succeeded";
12	}
13	else
14	{
15		std::cout << "mkdir failed";
16	}
17
18	return 0;
19}

2. 遍历文件夹

1#include<stdio.h>
2#include<stdlib.h>
3#include<unistd.h>
4#include<sys/stat.h>
5#include<string.h>
6#include<fcntl.h>
7#include<dirent.h>
8
9void TraversalFolder(const char *filedir)
10{
11	struct stat dirstat;
12	if (stat(filedir, &dirstat) == -1)
13	{
14		printf("cant access to %s", filedir);
15		exit(1);
16	}
17
18	if (dirstat.st_mode & S_IFDIR)
19	{
20		struct dirent *entry;
21		DIR * dir;
22		dir = opendir(filedir);
23		printf("%s\n", filedir);
24		while ((entry = readdir(dir)) != NULL)
25		{
26			if (!strcmp(entry->d_name, ".") || !strcmp(entry->d_name, ".."))continue;
27			char src[255];
28			strcpy(src, filedir);
29			strcat(src, "/");
30			chdir(strcat(src, entry->d_name));
31			TraversalFolder(src);
32			chdir(filedir);
33		}
34	}
35	else
36	{
37		printf("--%s\n", filedir);
38	}
39
40}
41int main(int argc, char *args[])
42{
43	if (argc != 2)
44	{
45		printf("param error");
46	}
47	TraversalFolder(args[1]);
48	return 0;
49}