在 c++98 Linux 中读取文件名作为命令行参数并执行文件操作 "open"

Question

我正在读取 abc.cpp 文件，该文件位于 /home/documents/abc.cpp 下。要打开文件，我正在执行文件操作 open("t.open("/home/documents/abc.cpp")。我可以在其中对文件执行打开操作。

我想尝试使用命令行参数读取文件名。所以我在这里尝试的是命令行

./a.out abc.cpp ，当我编译我会抛出编译错误的代码，如何解决这个问题请帮助。

#include <iostream>
#include <fstream> 
#include <sstream>
#include<string.h>
#include <ext/stdio_filebuf.h>

using namespace std; 
int main(int argc, char *argv[])
{
                ifstream t;
                string path = "/home/documents/";
                string file = path + argv[1];
                t.open(file);
                //t.open("/home/documents/abc.cpp");
                string buffer;
                string line;
                while(t)
                {
                        getline(t, line);
                        // ... Append line to buffer and go on
                        buffer += line;
                        buffer += "\n";
                }
                t.close();
return 0;
}

编译错误

g++ cmdLine.cpp
cmdLine.cpp: In function ‘int main(int, char**)’:
cmdLine.cpp:13:32: error: no matching function for call to ‘std::basic_ifstream<char>::open(std::string&)’
                     t.open(file);
                                ^
cmdLine.cpp:13:32: note: candidate is:
In file included from cmdLine.cpp:2:0:
/usr/include/c++/4.8.2/fstream:538:7: note: void std::basic_ifstream<_CharT, _Traits>::open(const char*, std::ios_base::openmode) [with _CharT = char; _Traits = std::char_traits<char>; std::ios_base::openmode = std::_Ios_Openmode]
       open(const char* __s, ios_base::openmode __mode = ios_base::in)
       ^
/usr/include/c++/4.8.2/fstream:538:7: note:   no known conversion for argument 1 from ‘std::string {aka std::basic_string<char>}’ to ‘const char*’

Answer 1

t.open(file.c_str()); 将解决您的问题。在 C++11 之前，唯一的函数声明是

void open( const char *filename,
           ios_base::openmode mode = ios_base::in );

错误消息非常清楚地告知您：没有已知的从“std::string”到“const char*”的转换。

在 c++98 Linux 中读取文件名作为命令行参数并执行文件操作 "open"

To read fileName as commandLine argument and perform file Operation "open" in c++98 Linux

c++

file

dynamic

command-line-arguments