Programming Forums > Application Development > C++

jack0987 · Mar 31st, 2008, 1:43 PM

Can somebody give me an idea how to start doing this??

Tasks:
1. There is one input file which contains a list of data with a number of columns and rows.
2. The file should be sorted according to different column(ranks, location...) depending on the input of the user.

My problem is that how should i read the rows so that it can be stored it in a structure, such that the file can be sorted according to one column at a time(e.g. according to the rank).

Should spaces be taken into consideration while reading the file??

thanks in advance for any help would be appreciated!

Freaky Chris · Mar 31st, 2008, 2:17 PM

Perhaps you could read the file line by line, and then split the string and store each value into and array, this way you can then access each value and say store it into an array for each coloumn. Checking for white space is a good way to know where to split your string. This may be helpful to you as to how you can cut the string. Also combine this with white space checking and you should have a solution to your problem.

Chris

Jimbo · Mar 31st, 2008, 9:00 PM

Like Chris said, you basically need to decide on a delimiting character to separate your columns. You could use a comma, which is fairly common. This of course means that none of your values can contain a comma (or whatever character you choose) unless you provide another marker to escape that value, which then makes the marker invalid unless you have a sequence to add it (think of how escaping with \ works; you can probably just use that, really).

lectricpharaoh · Apr 1st, 2008, 3:25 PM

How is the file laid out? Are the columns padded with spaces or tabs to line up nicely for a human reader, or is there some other delimiter used? Is the file even plain text, or is it a binary file made up of fixed-size records?

If it's a plain text file, perhaps you could post a small piece (half a dozen lines or so) of it here inside [code] [/code] tags to preserve the formatting, and we can offer more helpful suggestions.

jack0987 · Apr 1st, 2008, 3:57 PM

thanks again!!
here is how the file is laid out

(Toggle Plain Text)

 World Rank	Institution	             			Region	Regional Rank	Country		National Rank	Score on Alumni	Score on Award	Score on HiCi	Score on N&S	Score on SCI	Score on Size	Total Score
1	        Harvard Univ	            			Americas	1	USA			1		100		100	 	100		100		100		72.4		100
2	       Univ Cambridge	             			Europe		1	UK			1		99.8		93.4		53.3		56.6		70.9		66.9		73.6
3	       Stanford Univ	            			Americas	2	USA			2		41.1		72.2		88.5		70.9		72.3		65		73.4
4	      Univ California - Berkeley    			Americas	3	USA			3		71.8		76		69.4		73.9		72.2		52.7		72.8
5	    Massachusetts Inst Tech (MIT)  			Americas	4	USA			4		74		80.6		66.7		65.8		64.3		53		70.1
6	      California Inst Tech	   			Americas	5	USA			5		59.2		68.6		59.8		65.8		52.5		100		67.1
7	         Columbia Univ         				Americas	6	USA			6		79.4		60.6		56.1		54.2		69.5		45.4		62.3
8	          Princeton Univ				Americas	7	USA			7		63.4		76.8		60.9		48.7		48.5		59.1		60.9
9	            Univ Chicago				Americas	8	USA			8		75.6		81.9		50.3		44.7		56.4		42.2		60.1
10	            Univ Oxford	         			Europe	        2	UK			2		64.3		59.1		48.4		55.6		68.4		53.2		59.7
11	             Yale Univ  				Americas	9	USA			9		52.1		44.5		60.3		57.2		63.9		49.3		56.9
12	            Cornell Univ				Americas	10	USA			10		46.5		52.4		55		48.8		66.3		39.8		54.6
13	Univ California - San Diego				Americas	11	USA			11		17.7		34.7		59.8		56.5		64.5		46.6		51

mbd · Apr 3rd, 2008, 2:14 AM

here is a start. it copies standard input into a vector, sorts it, then copies the vector to standard output. this just uses a lexicographical string comparison.

 c++ Syntax (Toggle Plain Text) 
#include <string>
#include <vector>
#include <iterator>
#include <iostream>
#include <algorithm>
 
int main()
{
	std::vector< std::string > v;
	std::copy(std::istream_iterator< std::string >(std::cin), std::istream_iterator< std::string >(), std::back_insert_iterator< std::vector <std::string > >(v));
	std::sort(v.begin(), v.end());
	std::copy(v.begin(), v.end(), std::ostream_iterator< std::string >(std::cout, "\n"));
	return 0;
}
#include <string>
#include <vector>
#include <iterator>
#include <iostream>
#include <algorithm>

int main()
{
	std::vector< std::string > v;
	std::copy(std::istream_iterator< std::string >(std::cin), std::istream_iterator< std::string >(), std::back_insert_iterator< std::vector <std::string > >(v));
	std::sort(v.begin(), v.end());
	std::copy(v.begin(), v.end(), std::ostream_iterator< std::string >(std::cout, "\n"));
	return 0;
}

a good place for you to begin would to be overriding the < operator for std::string.

Mar 31st, 2008, 1:43 PM	#1
jack0987 Newbie Join Date: Mar 2008 Posts: 2 Rep Power: 0	C++ file sorting Can somebody give me an idea how to start doing this?? Tasks: 1. There is one input file which contains a list of data with a number of columns and rows. 2. The file should be sorted according to different column(ranks, location...) depending on the input of the user. My problem is that how should i read the rows so that it can be stored it in a structure, such that the file can be sorted according to one column at a time(e.g. according to the rank). Should spaces be taken into consideration while reading the file?? thanks in advance for any help would be appreciated!

Mar 31st, 2008, 2:17 PM	#2
Freaky Chris Hobbyist Programmer Join Date: Dec 2007 Location: England Posts: 169 Rep Power: 1	Re: C++ file sorting Perhaps you could read the file line by line, and then split the string and store each value into and array, this way you can then access each value and say store it into an array for each coloumn. Checking for white space is a good way to know where to split your string. This may be helpful to you as to how you can cut the string. Also combine this with white space checking and you should have a solution to your problem. Chris __________________ Who said i couldn't program `sarcasm = raw_input('Type in a sarcastic remark: ') print sarcasm`

Mar 31st, 2008, 9:00 PM	#3
Jimbo Battle Programmer Join Date: Feb 2006 Location: Bellevue, WA, USA Posts: 754 Rep Power: 3	Re: C++ file sorting Like Chris said, you basically need to decide on a delimiting character to separate your columns. You could use a comma, which is fairly common. This of course means that none of your values can contain a comma (or whatever character you choose) unless you provide another marker to escape that value, which then makes the marker invalid unless you have a sequence to add it (think of how escaping with \ works; you can probably just use that, really). __________________ <insert disclaimer here> <insert shameless plug for Visual Studio here>

Apr 1st, 2008, 3:25 PM	#4
lectricpharaoh Caffeinated Neural Net Join Date: Jun 2005 Location: Dry west coast of Canada Posts: 1,011 Rep Power: 5	Re: C++ file sorting How is the file laid out? Are the columns padded with spaces or tabs to line up nicely for a human reader, or is there some other delimiter used? Is the file even plain text, or is it a binary file made up of fixed-size records? If it's a plain text file, perhaps you could post a small piece (half a dozen lines or so) of it here inside [code] [/code] tags to preserve the formatting, and we can offer more helpful suggestions. __________________ And once again, Probability proves itself willing to sneak into a back alley and service Drama as would a copper-piece harlot. - Vaarsuvius, Order of the Stick

Apr 1st, 2008, 3:57 PM	#5
jack0987 Newbie Join Date: Mar 2008 Posts: 2 Rep Power: 0	Re: C++ file sorting thanks again!! here is how the file is laid out (Toggle Plain Text) World Rank Institution Region Regional Rank Country National Rank Score on Alumni Score on Award Score on HiCi Score on N&S Score on SCI Score on Size Total Score 1 Harvard Univ Americas 1 USA 1 100 100 100 100 100 72.4 100 2 Univ Cambridge Europe 1 UK 1 99.8 93.4 53.3 56.6 70.9 66.9 73.6 3 Stanford Univ Americas 2 USA 2 41.1 72.2 88.5 70.9 72.3 65 73.4 4 Univ California - Berkeley Americas 3 USA 3 71.8 76 69.4 73.9 72.2 52.7 72.8 5 Massachusetts Inst Tech (MIT) Americas 4 USA 4 74 80.6 66.7 65.8 64.3 53 70.1 6 California Inst Tech Americas 5 USA 5 59.2 68.6 59.8 65.8 52.5 100 67.1 7 Columbia Univ Americas 6 USA 6 79.4 60.6 56.1 54.2 69.5 45.4 62.3 8 Princeton Univ Americas 7 USA 7 63.4 76.8 60.9 48.7 48.5 59.1 60.9 9 Univ Chicago Americas 8 USA 8 75.6 81.9 50.3 44.7 56.4 42.2 60.1 10 Univ Oxford Europe 2 UK 2 64.3 59.1 48.4 55.6 68.4 53.2 59.7 11 Yale Univ Americas 9 USA 9 52.1 44.5 60.3 57.2 63.9 49.3 56.9 12 Cornell Univ Americas 10 USA 10 46.5 52.4 55 48.8 66.3 39.8 54.6 13 Univ California - San Diego Americas 11 USA 11 17.7 34.7 59.8 56.5 64.5 46.6 51 World Rank Institution Region Regional Rank Country National Rank Score on Alumni Score on Award Score on HiCi Score on N&S Score on SCI Score on Size Total Score 1 Harvard Univ Americas 1 USA 1 100 100 100 100 100 72.4 100 2 Univ Cambridge Europe 1 UK 1 99.8 93.4 53.3 56.6 70.9 66.9 73.6 3 Stanford Univ Americas 2 USA 2 41.1 72.2 88.5 70.9 72.3 65 73.4 4 Univ California - Berkeley Americas 3 USA 3 71.8 76 69.4 73.9 72.2 52.7 72.8 5 Massachusetts Inst Tech (MIT) Americas 4 USA 4 74 80.6 66.7 65.8 64.3 53 70.1 6 California Inst Tech Americas 5 USA 5 59.2 68.6 59.8 65.8 52.5 100 67.1 7 Columbia Univ Americas 6 USA 6 79.4 60.6 56.1 54.2 69.5 45.4 62.3 8 Princeton Univ Americas 7 USA 7 63.4 76.8 60.9 48.7 48.5 59.1 60.9 9 Univ Chicago Americas 8 USA 8 75.6 81.9 50.3 44.7 56.4 42.2 60.1 10 Univ Oxford Europe 2 UK 2 64.3 59.1 48.4 55.6 68.4 53.2 59.7 11 Yale Univ Americas 9 USA 9 52.1 44.5 60.3 57.2 63.9 49.3 56.9 12 Cornell Univ Americas 10 USA 10 46.5 52.4 55 48.8 66.3 39.8 54.6 13 Univ California - San Diego Americas 11 USA 11 17.7 34.7 59.8 56.5 64.5 46.6 51

Apr 3rd, 2008, 2:14 AM	#6
mbd Programmer Join Date: Nov 2007 Posts: 86 Rep Power: 1	Re: C++ file sorting here is a start. it copies standard input into a vector, sorts it, then copies the vector to standard output. this just uses a lexicographical string comparison. c++ Syntax (Toggle Plain Text) #include <string> #include <vector> #include <iterator> #include <iostream> #include <algorithm> int main() { std::vector< std::string > v; std::copy(std::istream_iterator< std::string >(std::cin), std::istream_iterator< std::string >(), std::back_insert_iterator< std::vector <std::string > >(v)); std::sort(v.begin(), v.end()); std::copy(v.begin(), v.end(), std::ostream_iterator< std::string >(std::cout, "\n")); return 0; } #include <string> #include <vector> #include <iterator> #include <iostream> #include <algorithm> int main() { std::vector< std::string > v; std::copy(std::istream_iterator< std::string >(std::cin), std::istream_iterator< std::string >(), std::back_insert_iterator< std::vector <std::string > >(v)); std::sort(v.begin(), v.end()); std::copy(v.begin(), v.end(), std::ostream_iterator< std::string >(std::cout, "\n")); return 0; } a good place for you to begin would to be overriding the < operator for std::string.

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Programming Forums > Application Development > C++

C++ file sorting