Thread: "fin." usage

Use getline().

Code:

    string message;
    cout << "Enter a message:" << endl;
    getline(cin, message);

Code:

#include <fstream.h>
#include <iostream.h>
#include <string.h>

These are the older headers, use the new ones:

Code:

#include <fstream>
#include <iostream>
#include <cstring>  // Or <string>?  Either way, you don't look like you really need this one

Code:

using namespace std;

int main()
{
    ifstream fin("file1.txt");
    char message[512];
    cout << "Enter a message:" << endl;
    cin >> message ;
    fin.open("file1.txt",ios::app);

Your code is trying to open a file twice, the first line after the '{' opens a file called file1.txt for input. The fin.open() command then tries again to open the same file in append mode. Of course you should only need to open the file for input once. Also, append mode is only for output files, not input files.

Code:

    fin.getline(message, 512);

This is going to overwrite whatever the user typed into the buffer in response to the above prompt to enter a message. Are you simply thowing that input away in favor of getting a line from the input file or do you need to do something with that input before you get the line from the file?

Code:

    ofstream SaveFile("file1.txt",ios::app);

    SaveFile << message;
    SaveFile << ".\n" ;
    SaveFile.close();
    return 0;
}

You should probably close the input file fin before you open another file object referencing the same file. The declaration of the SaveFile object needs to do a bitwise OR with ios::out, i.e. ofstream SaveFile("file1.txt",ios::out|ios::app);

What sentence are you trying to write (append?) to the file? The one you appear to be reading from the input file, or the one you get from the user at the prompt?

1. Using a string object would require the <string> header instead of the <cstring> header.

2. You are still attempting to open the input file twice.

3. You are still trying to use append mode on an input file.

4. Why do you even need an input file if you aren't using it for anything?

Originally Posted by osiris_99

Its saying "SaveFile" is an undeclared funtion.

Because you have commented out the line which declares the SaveFile object, i.e.:

Code:

//ofstream SaveFile("file1.txt",ios::app);

You are attempting to use the SaveFile object in the lines below this point and it hasn't been declared anywhere because you have it commented out... that is why you get that message.

If you simply want to get a message from the user, and append that to a file:

Code:

#include <fstream>
#include <iostream>
#include <string>
#include <cstdlib> // For EXIT_FAILURE, EXIT_SUCCESS

using namespace std;

int main()
{
    string message;
    ofstream SaveFile("file1.txt",ios::out|ios::app);

    // Make sure file is open, if not exit program
    if(!SaveFile.is_open())
    {
        cout << "Error attempting to open output file." << endl;
        return EXIT_FAILURE;
    }

    // Get message from user
    cout << "Enter a message: ";
    getline(cin,message);

    // Write/append message to end of file
    SaveFile << message << endl;

    return EXIT_SUCCESS;

}