#include <iostream>
#include <string>
#include <fstream>
#include <filesystem>
using namespace std;
//C++11之前
bool FileExist1(const string &filename)
{
ifstream f(filename.c_str());
return f.good();//检测流的状态是否正常。当错误的状态flags (eofbit, failbit and badbit) 都没被设置的时候返回true
}
//C风格写法
bool FileExist2(const string &filename)
{
//以只读方式打开文件
FILE *p_file = fopen(filename.c_str(), "r");
if (p_file)
{
fclose(p_file);
return true;
}
else
{
return false;
}
}
//C++11
bool FileExist3(const string &filename)
{
return std::experimental::filesystem::exists(filename);
}
//C++17,如果编译不过,需要在项目属性,C/C++->语言->检查语言标准中设置C++17以上
bool FileExist4(const string &filename)
{
return std::filesystem::exists(filename);
}
int main()
{
string filename = "FileExist.cpp";
//bool ret = FileExist1(filename);
//bool ret = FileExist2(filename);
//bool ret = FileExist3(filename);
bool ret = FileExist4(filename);
if (ret)
{
cout << "文件存在" << endl;
}
else
{
cout << "文件不存在" << endl;
}
}