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Having problems compiling my .cpp file on Linux

For some reason my code is not compiling on a linux server. It gives me several ofstream, ifstream, and fstream errors. It compiles perfectly fine on a windows machine. I have never tried to compile a c++ program on linux before so this could be a dumb mistake.

This is just a simple program that copies one file to another file and checks for different errors.

Thanks for any help!

Code:

#include <iostream>

#include <fstream>

#include <string>



bool fileExists(const std::string);



//Bool function to test if output file already exists

bool fileExists(const std::string fileName)

{

        std::ifstream infile(fileName);

        return infile.good();

}





int main()

{

        std::ifstream file_in;//declares the input file

        std::ofstream file_out;//declares the output file

        std::string filename_in, filename_out;//declares the file strings

        

        //Name prompt for input file

        std::cout<<"What is the name of the input file?\n";

        std::cin>>filename_in;



        //Opens the input file

        file_in.open(filename_in, std::ios::in);



        //Error if input file fails

        if(file_in.fail())

        {

                //Gives error message and aborts

                std::cout<<"\nThe filename "<<filename_in<<" could not be read.\n";

                std::cout<<"Possible errors include:\n";

                std::cout<<"A - The file-path was not found or\n";

                std::cout<<"B - The file does not exist.\n\n";

                std::system("pause");

                exit(1);

        }



        std::cout<<"What is the name of the output file?\n";

        std::cin>>filename_out;



        //Checks to see if a file already exists

        if(fileExists(filename_out))

        {

                //Gives error message and aborts

                std::cout<<"\nThe filename "<<filename_out<<" already exists!\n";

                std::cout<<"ABORTING FILE COPY!\n\n";

                system("pause");

                exit(1);

        }



        //Opens the output file for writing

        file_out.open(filename_out, std::ios::out);



        //Loop that reads input and writes to output file

        char inp;

        while(!file_in.eof())

        {

                //reads the input char

                file_in.get(inp);

                //does not read eof char on last loop

                if(!file_in.eof())

                {

                        file_out<<inp;

                }

        }



        //closes files

        file_in.close();

        file_out.close();



        std::cout<<"\nCopy Successful!\n";//Success message



        return 0;

}

I have to admmit that the c++ compiler errors are sometimes somewhat hard to read, especially because very long type names and function prototypes. They are, however quite clear:

Code:

main.cpp: In function ‘bool fileExists(std::string)’:

main.cpp:10:31: error: no matching function for call to ‘std::basic_ifstream<char>::basic_ifstream(const string&)’

main.cpp:10:31: note: candidates are:

In file included from main.cpp:2:0:

/usr/lib64/gcc/x86_64-slackware-linux/4.7.1/../../../../include/c++/4.7.1/fstream:460:7: note: std::basic_ifstream<_CharT, _Traits>::basic_ifstream(const char*, std::ios_base::openmode) [with _CharT = char; _Traits = std::char_traits<char>; std::ios_base::openmode = std::_Ios_Openmode]

/usr/lib64/gcc/x86_64-slackware-linux/4.7.1/../../../../include/c++/4.7.1/fstream:460:7: note:  no known conversion for argument 1 from ‘const string {aka const std::basic_string<char>}’ to ‘const char*’

...

fstream has no constructor that takes a string as an argument. It takes const char* instead. The compiler does not know how to convert string to const char*.
You can do this by calling the method string::c_str(). So,

Code:

std::ifstream infile(fileName.c_str());

should solve the problem. The same bug appears in several other places in the code. Another error is:

Code:

main.cpp:36:3: error: ‘system’ is not a member of ‘std’

main.cpp:37:9: error: ‘exit’ was not declared in this scope

These require

Code:

#include <cstdlib>

Anyway, system("PAUSE"); is a non-portable windows bad habit that will not work in linux. There are many threads around that discuss this, so just search for them.

Another note:

Code:

bool fileExists(const std::string);

I would recommend to pass strings (and other large objects) by reference, rather than by value to avoid unnecessary copying.

Code:

bool fileExists(const std::string&);

Perfect! That fixed it.

And thanks for the reference suggestion. It's been a while since i've programmed in c++ so I didn't think that through all of the way.