rewind stream or use peek?

[drdaco]

Hi Everyone, retrying c++ after a 10 year hiatus. F/C scientific programmer here :)

So I have this really really long data file. It has a header and I want to locate the heading just before the data rows begin. The heading size may change from different sources, but the heading is always the same. So it's something like

{
long header
}
{column titles = AAA BBB CCC DDD EEE ... ZZZ}
{data columns = 111 222 333 444 555 ... 666}
.
.
.
{data columns = 111 222 333 444 555 ... 666}

I got my proggy to read each line and find the first word of the header and check it and then begin reading data...using:

getline(snp_file_in, word, ' ');

but I want to output the header also...but I realized that using

getline(snp_file_in, line);

moves my buffer...

is there a way to rewind the stream pointer? All the examples for peek use characters and I need at least three characters to check if I've reached the heading....and I need to read and output the header.

[MosaicFuneral]

Perhaps this?: http://www.cplusplus.com/reference/iostream/istream/seekg/

[drdaco]

perhaps but I don't know how I can implement that to do the check in the meanwhile. What I could do is simply read the file, count the lines until I get my header, put the pointer back, reread + print and then read data.

I was hoping to cut out the rewind part but perhaps it's easiest to implement this way.