使用字符串作为打开文件路径的 C++ ifstream 错误。
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C++ ifstream error using string as opening file path.
提问by Mark
I have:
我有：
string filename:
ifstream file(filename);
The compilers complains about no match between ifstream file and a string. Do I need to convert filename to something?
编译器抱怨 ifstream 文件和字符串之间不匹配。我需要将文件名转换为什么吗？
Here's the error:
这是错误：
error: no matching function for call to ‘std::basic_ifstream<char, std::char_traits<char> >::basic_ifstream(std::string&)'
/usr/include/c++/4.4/fstream:454: note: candidates are: std::basic_ifstream<_CharT, _Traits>::basic_ifstream(const char*, std::_Ios_Openmode) [with _CharT = char, _Traits = std::char_traits<char>]
回答by Seth Carnegie
Change
改变
ifstream file(filename);
to
到
ifstream file(filename.c_str());
Because the constructor for an ifstreamtakes a const char*, not a stringpre-C++11.
因为 an 的构造函数ifstream需要一个const char*，而不是一个stringpre-C++11。
回答by Alexander Gessler
The ifstreamconstructor expects a const char*, so you need to do ifstream file(filename.c_str());to make it work.
该ifstream构造函数需要一个const char*，所以你需要做的ifstream file(filename.c_str());，以使其正常工作。
回答by evi v
in c++-11 it can also be an std::string. So (installing c++-11 and) changing the dialect of you project to c++-11 could also fix the problem.
在 c++-11 中，它也可以是 std::string。因此（安装 c++-11 和）将项目的方言更改为 c++-11 也可以解决问题。
