Copying one text file to another

[Gactimus]

I wrote a C++ program that is supposed to copy one text file to another.
It works fine if I specify the files to be opened and copied but when I
try to have the file names inputted by the user it doesn't work and I am
stumped. Can anyone clue me in to what I am missing?

Here is my code:


#include <iostream>
#include <fstream>
#include <cstdlib>
#include <string>
using namespace std;

int main()
{
string source;
string clone;

cout << "Enter the source file: ";
cin >> source;
cout << "Enter the name of the new file: ";
cin >> clone;

ifstream in(source.c_str); // Open for reading
ofstream out(clone.c_str); // Open for writing
string s;
while(getline(in, s))
out << s << "\n";

return 0;
}

 

[ES Kim]

I wrote a C++ program that is supposed to copy one text file to another.
It works fine if I specify the files to be opened and copied but when I
try to have the file names inputted by the user it doesn't work and I am
stumped. Can anyone clue me in to what I am missing?

Here is my code:

ifstream in(source.c_str); // Open for reading
ofstream out(clone.c_str); // Open for writing

ifstream in(source.c_str());
ofstream out(clone.c_str());

 

[Gactimus]

ifstream in(source.c_str());
ofstream out(clone.c_str());

D'oh! It's always the stupid mistakes that get you. Thanks.

 

[Someonekicked]

a faster way would be reading all the file at once ( not looping throughout
lines), maybe it would not be a remarquable difference, anyway you can use
getline(in,s,char(0));
char(0) is the null character, so the delimiter is the null character ( when
reading no more characters).

 

[Gactimus]

a faster way would be reading all the file at once ( not looping
throughout lines), maybe it would not be a remarquable difference,
anyway you can use getline(in,s,char(0));
char(0) is the null character, so the delimiter is the null character (
when reading no more characters).

Thanks for the info. On a side note, do you know how I would go about
encrypting the file that is copied? I want to do it very simply, as in
adding 1 to every ASCII character.

 

[Gactimus]

Of course, you can add '1' or do whatever you like with the character
before you write it to the output file stream.

Thanks. I'll try it out.

 

[Gactimus]

Of course, you can add '1' or do whatever you like with the character
before you write it to the output file stream.

Of course, you can add '1' or do whatever you like with the character
before you write it to the output file stream.

It put the code in the program but I get an error:

error C2039: 'get' : is not a member of 'basic_string<char,struct std::char_traits<char>,class std::allocator<char> >'

Any ideas? Maybe I just don't know how to implement your code.

 

[=?ISO-8859-1?Q?Ney_Andr=E9_de_Mello_Zunino?=]

Thanks for the info. On a side note, do you know how I would go about
encrypting the file that is copied? I want to do it very simply, as in
adding 1 to every ASCII character.

Then read it character by character. Something like (untested):

char c;
while (source.get(c))
clone.put(c);

Hope that helps,

 

[=?ISO-8859-1?Q?Ney_Andr=E9_de_Mello_Zunino?=]

Then read it character by character. Something like (untested):

char c;
while (source.get(c))
clone.put(c);

Of course, you can add '1' or do whatever you like with the character
before you write it to the output file stream.

 

[John Harrison]

It put the code in the program but I get an error:

error C2039: 'get' : is not a member of 'basic_string<char,struct
std::char_traits<char>,class std::allocator<char> >'

Any ideas? Maybe I just don't know how to implement your code.

source and clone are not strings, they are the file streams. What you called
in and out in your original code.

Incidentally I would not use the method that Someonekicked recommended, it
does not work if your file contains a null byte. Nor would I use the method
you had originally because that adds an extra newline when the original file
does not end in a newline. Reading and writing one character at a time as
Andre recommended is the simplest.

john

 

[Karl Heinz Buchegger]

It put the code in the program but I get an error:

error C2039: 'get' : is not a member of 'basic_string<char,struct std::char_traits<char>,class std::allocator<char> >'

Any ideas? Maybe I just don't know how to implement your code.

Look at the error message. What does it talk about?

It talks about basic_string. Hmm. basic_string. That has something
to do with string! It says that 'get' is not a member of some string
class. But why string? get is something you want to apply to a stream
not a string. So chances are high that you used the wrong variable and
applied get to it. You want to get from the stream and not the string.

I know. Those error messages are cryptic and sometimes even
misleading. But you definitly *must* learn to read them and
draw your conclusions from them.

 

[Francis Glassborow]

Then read it character by character. Something like (untested):

char c;
while (source.get(c))
clone.put(c);

Hope that helps,

Actually there is a subtle problem waiting to bite if you open the files
in text mode; sometimes the encryption mechanism will generate a control
character which will cause problems with reading the encrypted file. It
is, therefore, much safer when encrypting/decrypting a file to open the
file in binary mode.

 

[Chris \( Val \)]

|
| > Ney André de Mello Zunino wrote:
| >
| >> Then read it character by character. Something like (untested):
| >>
| >> char c;
| >> while (source.get(c))
| >> clone.put(c);
| >
| > Of course, you can add '1' or do whatever you like with the character
| > before you write it to the output file stream.
|
|
| > Ney André de Mello Zunino wrote:
| >
| >> Then read it character by character. Something like (untested):
| >>
| >> char c;
| >> while (source.get(c))
| >> clone.put(c);
| >
| > Of course, you can add '1' or do whatever you like with the character
| > before you write it to the output file stream.
|
| It put the code in the program but I get an error:
|
| error C2039: 'get' : is not a member of 'basic_string<char,struct
std::char_traits<char>,class std::allocator<char> >'
|
| Any ideas? Maybe I just don't know how to implement your code.

One method I can think of to copy a file is to open
the file in binary mode, and use the 'rdbuf()' member:

out << in.rdbuf();

Cheers.
Chris Val