streamWriter rewrite the file or append to the file

Question

I am using this

for($number=0; $number < 5; $number++){
StreamWriter x = new StreamWriter("C:\\test.txt");
                x.WriteLine(number);
                x.Close();

}

if something is in test.text, this code will not overwrite it. I have 2 questions

1: how can I make it overwrite the file
2: how can I append to the same file

using C#

Answer 1

Try the FileMode enumerator:

        FileStream fappend = File.Open("C:\\test.txt", FileMode.Append); // will append to end of file

        FileStream fcreate = File.Open("C:\\test.txt", FileMode.Create); // will create the file or overwrite it if it already exists

Answer 2

StreamWriters default behavior is to create a new file, or overwrite it if it exists. To append to the file you'll need to use the overload that accepts a boolean and set that to true. In your example code, you will rewrite test.txt 5 times.

using(var sw = new StreamWriter(@"c:\test.txt", true))
{
    for(int x = 0; x < 5; x++)
    {
        sw.WriteLine(x);    
    }
}

Answer 3

You can pass a second parameter to StreamWriter to enable or disable appending to file:

in C#.Net:

using System.IO;

// This will enable appending to file.
StreamWriter stream = new StreamWriter("YourFilePath", true);

// This is default mode, not append to file and create a new file.
StreamWriter stream = new StreamWriter("YourFilePath", false);
// or
StreamWriter stream = new StreamWriter("YourFilePath");

in C++.Net(C++/CLI):

using namespace System::IO;

// This will enable appending to file.
StreamWriter^ stream = gcnew StreamWriter("YourFilePath", true);

// This is default mode, not append to file and create a new file.
StreamWriter^ stream = gcnew StreamWriter("YourFilePath", false);
// or
StreamWriter^ stream = gcnew StreamWriter("YourFilePath");