Finding carriage returns (\c) in a line

Hi all:

I'm trying to write a few lines of code that will take a line of input and replace an instance of "\c" with the carriage return character 0xD, and then search a document for that line of input.

For example, here's a test file (assume saved in Windows format, so each carriage return is \c\l):

Code:

Line 1
Line 2
Line 3
Another line 1 but not newline after

What I want to do is search for "1\c" and have the program return "Line 1"

My current algorithm is:

Code:

char c = 0xD;
string::size_type pos = contains.find("\\c");
string carriageReturn(1, c);
contains.replace(pos, 2, carriageReturn);

However, this doesn't seem to be working. Any other ideas?

Thanks.

The escape character for a carriage return is '\r'.

Originally Posted by Prelude

The escape character for a carriage return is '\r'.

Hm, are you sure? I'm looking at the table here http://www.lookuptables.com/ and it seems like it's 15, 0xD?

I just used \c as an example in the input. For example, it takes "1\c" as the input and should look for 1 followed by 0xD in the file.

http://www.cppreference.com/escape_sequences.html

Thanks guys. I may be a bit dense here, but I'm not sure how I can implement that. Any leads?

Thanks again.

Windows line break is a CRLF - control return (\r) line feed (\n). find("\\r\\n") in a loop, and replace it with "\r\n".

Make sure you're reading-in the file in binary format. If you read it in as text, you will never see CR/LF. It's going to "translate" CR/LF to a NULL-termination for the C-style string format.

Thanks guys. I'll take a look.

Originally Posted by DougDbug

Make sure you're reading-in the file in binary format. If you read it in as text, you will never see CR/LF. It's going to "translate" CR/LF to a NULL-termination for the C-style string format.

Yup. I have this working for the \t tab character, just not for the new lines.

Originally Posted by Tonto

Windows line break is a CRLF - control return (\r) line feed (\n). find("\\r\\n") in a loop, and replace it with "\r\n".

I did this, and it still didn't work .

Show us what you tried, I guess.

Originally Posted by twomers

Show us what you tried, I guess.

Yeah, I should've done that in the previous post:

Code:

else if (contains[contains.size() - 2] == '\\' && contains[contains.size() - 1] == 'c')
	{
		string::size_type pos = contains.find("\\c");
		//cout <<pos <<endl;
		string carriageReturn(1, c);
		cout <<contains <<endl;
		contains.replace(pos, 2, "\r");

		cout <<contains <<endl;
	}

Bump .

Bumping is against the rules.

I think the mistake is that you are looking for a sequence of characters like \ and c (should be r?) in the text file, which clearly isn't there. Instead there is an invisible character (well, you see it as a new line beginning), that is represented as an escape sequence '\r', but is really a single character (that has ASCII value of 13).

Apart from that, the block executes if the last two characters of the string are \ and c. It means you know they are there, why would you use find to find their position again.