How do I read and edit a .txt file in C#?

Question

For example, I have a txt file that reads:

12 345 45
2342 234 45 2 2 45345
234 546 34 3 45 65 765
12 23 434 34 56 76 5

I want to insert a comma between all the numbers, add a left brace to the begining of each line and a right brace to the end of each line. So after the editing it should read:

{12, 345, 45}
{2342, 234, 45, 2, 2, 45345}
{234, 546, 34, 3, 45, 65, 765}
{12, 23, 434, 34, 56, 76, 5}

How do I do it?

Answer 1

Added some LINQ for fun and profit (room for optimization ;) ):

System.IO.File.WriteAllLines(
    "outfilename.txt",
    System.IO.File.ReadAllLines("infilename.txt").Select(line =>
        "{" +
        string.Join(", ",
            line.Split(new string[] { " " }, StringSplitOptions.RemoveEmptyEntries)
        ) + "}"
    ).ToArray()
);