Writing a string to the end of a file (C++)

Question

I have a program already formed that has a string that I want to stream to the end of an existing text file. All of what little I have is this: (C++)

 void main(         


        

Answer 1

Open your stream as append, new text written to it will be written at the end of the file.

Answer 2

Open your file using std::ios::app

 #include <fstream>

 std::ofstream out;

 // std::ios::app is the open mode "append" meaning
 // new data will be written to the end of the file.
 out.open("myfile.txt", std::ios::app);

 std::string str = "I am here.";
 out << str;

Answer 3

To append contents to the end of files, simply open a file with ofstream (which stands for out file stream) in app mode (which stands for append).

#include <fstream>
using namespace std;

int main() {
    ofstream fileOUT("filename.txt", ios::app); // open filename.txt in append mode

    fileOUT << "some stuff" << endl; // append "some stuff" to the end of the file

    fileOUT.close(); // close the file
    return 0;
}

Answer 4

I hope that isn't your whole code because if it is, there's lots of things wrong with it.

The way you would write out to a file looks something like this:

#include <fstream>
#include <string>

// main is never void
int main()
{
    std::string message = "Hello world!";

    // std::ios::out gives us an output filestream
    // and std::ios::app appends to the file.
    std::fstream file("myfile.txt", std::ios::out | std::ios::app);
    file << message << std::endl;
    file.close();

    return 0;
}