Find multiple new lines char

abhisheknayak · 12-13-2007, 11:47 PM

Hi,
I want extract the text from a text file when the word "Positive" appears until a new line character( '\n') is repeated 3 times in continuation, how do I do it in c++. The problem using peek() is it detects only single character and if I write ( file.peek() =="\n\n\n"). it isn't giving me the required result. Below is the way how I tried.

fstream iF;
iF.open("filename");
char test1[50];

do{
iF>>test1;
if (strcmp(test1,"Positives")== 0)
{
do{
iF.get(ch);
cout<<ch;
}while( iF.peek() != '\n' && iF.peek() != EOF);

//now iF.peek() != "\n\n\n" wont work
}
}while(iF.peek() != EOF);

See the sample file below

/////////////

Score = 58.2 bits (139), Expect = 9e-08
Identities = 27/141 (19%), Positives = 65/141 (45%)

Query: 9 NVGNIVLRLTNIGLKIMKVGPKIPNVRPNVGNIGPIITKVGLTCSNIGPNITNVGLKLTN 68
N + L + +G+ + VG + N+ +G + VG+ S +G + +G+ ++
Sbjct: 431 NASGVGLTASGMGMNMSGVGLTASGMGMNMSGVGLTASGVGMNMSGVGLTASGMGMNMSG 490

Query: 69 LGLKLTNLGLKLTNIGPKIMKVGPQRPNVGPNVGNIGPNITNIGPKVMKVDPEIPNIGPN 128
+GL + +G+ ++ +G +G VG +G N++ +G + + +G
Sbjct: 491 VGLTASGMGMNMSGVGLTASGMGMNMSGVGLTASGMGMNMSGVGLTASGMGMNMSGVGLT 550

Query: 129 VGNIGPKITNLGHKGTSVGLN 149
+G ++ +G + +G+N
Sbjct: 551 ASGMGMNMSGVGLTASGMGMN 571

////////////////

Tinkster · 12-15-2007, 12:04 PM

Well ... all you need to do is take count of "\n" as
you encounter it, reset the count to zero if a non-"\n"
follows.

Cheers,
Tink

Hivemind · 12-15-2007, 04:51 PM

This seems to work.

Code:

#include <fstream>
#include <iostream>
#include <string>

using namespace std;

int
main()
{
   ifstream infile("test.txt");

   if (!infile)
   {
      cerr << "Error opening file test.txt." << endl;

      return 1;
   }

   unsigned short consequtive_newlines_count = 0;
   string line;
   bool positives_string_found = false;

   while (getline(infile, line) && consequtive_newlines_count < 3)
   {
      if (line.find("Positives") != string::npos)
      {
         positives_string_found = true;
      }

      if (positives_string_found)
      {
         cout << line << endl;

         if (line.empty())
         {
            ++consequtive_newlines_count;
         }
         else
         {
            consequtive_newlines_count = 0;
         }
      }
   }

It assumes that three newlines have to be on an otherwise empty line, i.e. three empty lines will break the output. It doesn't count the newline just before an empty line.

For the following file test.txt

Code:

/////////////

Score = 58.2 bits (139), Expect = 9e-08
Identities = 27/141 (19%), Positives = 65/141 (45%)

Query: 9 NVGNIVLRLTNIGLKIMKVGPKIPNVRPNVGNIGPIITKVGLTCSNIGPNITNVGLKLTN 68
N + L + +G+ + VG + N+ +G + VG+ S +G + +G+ ++
Sbjct: 431 NASGVGLTASGMGMNMSGVGLTASGMGMNMSGVGLTASGVGMNMSGVGLTASGMGMNMSG 490

Query: 69 LGLKLTNLGLKLTNIGPKIMKVGPQRPNVGPNVGNIGPNITNIGPKVMKVDPEIPNIGPN 128
+GL + +G+ ++ +G +G VG +G N++ +G + + +G
Sbjct: 491 VGLTASGMGMNMSGVGLTASGMGMNMSGVGLTASGMGMNMSGVGLTASGMGMNMSGVGLT 550

Query: 129 VGNIGPKITNLGHKGTSVGLN 149
+G ++ +G + +G+N
Sbjct: 551 ASGMGMNMSGVGLTASGMGMN 571




////////////////

the output is

Code:

$ ./runme.exe
Identities = 27/141 (19%), Positives = 65/141 (45%)

Query: 9 NVGNIVLRLTNIGLKIMKVGPKIPNVRPNVGNIGPIITKVGLTCSNIGPNITNVGLKLTN 68
N + L + +G+ + VG + N+ +G + VG+ S +G + +G+ ++
Sbjct: 431 NASGVGLTASGMGMNMSGVGLTASGMGMNMSGVGLTASGVGMNMSGVGLTASGMGMNMSG 490

Query: 69 LGLKLTNLGLKLTNIGPKIMKVGPQRPNVGPNVGNIGPNITNIGPKVMKVDPEIPNIGPN 128
+GL + +G+ ++ +G +G VG +G N++ +G + + +G
Sbjct: 491 VGLTASGMGMNMSGVGLTASGMGMNMSGVGLTASGMGMNMSGVGLTASGMGMNMSGVGLT 550

Query: 129 VGNIGPKITNLGHKGTSVGLN 149
+G ++ +G + +G+N
Sbjct: 551 ASGMGMNMSGVGLTASGMGMN 571



$

abhisheknayak · 12-17-2007, 03:27 AM

Thanks the problem is fixed