Question

I have an input string that looks something like this:

4 Bob 32 Joe 64 Sue 123 Bill 42

Where the 4 indicates the number of string integer pairs to follow. My current way of processing this looks something like this:

var strings = input.Split(' ');
int count = Int32.Parse(strings[0]);
for ( int i = 0; i < count; i++ )
{
  string name = strings[count*2 + 1];
  int number = Int32.Parse(strings[count*2 + 1]);
  ProcessPerson(name, number);
}

This feels quite cumbersome. Is there some library in C# that can wrap a string and give me services like “readInt” and “readString”. I would ultimately like to have something like:

int count = input.ReadInt();
for(int i = 0; i<count; i++)
{
  ProcessPerson(input.ReadString(), input.ReadInt());
}

It doesn’t look like that much of an improvement in this case, but my actual object model is a bit more complicated. I know other languages have facilities to o things like this, but I can’t recall any .net libraries to simply read from the front of a string.

Answer 1

You could easily write such a “library” yourself:

class Parser
{
    private readonly Queue<string> m_parts;

    public Parser(string s)
    {
        m_parts = new Queue<string>(s.Split(' '));
    }

    public string ReadString()
    {
        return m_parts.Dequeue();
    }

    public int ReadInt32()
    {
        return int.Parse(ReadString());
    }
}

If the string could be large, or you are reading it from a stream, you have to do the splitting yourself:

class StreamParser
{
    private readonly TextReader m_reader;

    public StreamParser(string s)
        : this(new StringReader(s))
    {}

    public StreamParser(TextReader reader)
    {
        m_reader = reader;
    }

    public string ReadString()
    {
        var result = new StringBuilder();
        int c = m_reader.Read();
        while (c != -1 && (char)c != ' ')
        {
            result.Append((char)c);
            c = m_reader.Read();
        }

        if (result.Length > 0)
            return result.ToString();

        return null;
    }

    public int ReadInt32()
    {
        return int.Parse(ReadString());
    }
}