Strange results in std::string.substr()

[dbridle]

Hello everyone,

This is my first time posting and I'm happy to be here! I have not used C++ in a long time, however a project that I am involved with, has me writing quite a bit of C++ and my memory fails me at times! Here is my problem.

I am reading a file line by line into a string vector and then using the vector to creating several strings, used as properties in a class later on.

I'm using substr to grab only the data I need, and this is where the problem is.

Here is the code excerpt:

        int indexCh1;
	int indexCh2;

	indexCh1 = text_file[1].find("\"");
	indexCh2 = text_file[1].find("\"",3);

	strToName = text_file[1].substr(indexCh1+1, indexCh2-1);

	indexCh1 = text_file[1].find("<");
	indexCh2 = text_file[1].find(">");

	strToEmail = text_file[1].substr(indexCh1, indexCh2-1);

What I can't quite figure out, is why indexCh2-1 is not working. I have tried reducing the counter by one in the line before with indexCh2-- but with the same results. The actual full string looks like this:

["My Name" <[e-mail]>]

The first substring results in My Name"
The second substring results in [e-mail]>]

Always the indexCh1+1 and indexCh2+2 work, but never the -1.

Any idea's why this might be happening?

Thanks in advance,

Darren

[Disch]

The second param is the number of character you want to pull. It is not another position (like you seem to be thinking)

For example:

string foo = "0123456789";
string bar = foo.substr(2,3);

cout << bar;  // prints "234"
// the substring starts from position 2
//  and pulls 3 characters 

[dbridle]

Ah that makes more sense, I seem to have misread the MSDN page for it!

Thanks for your help, much appreciated.

Darren