programming


IEEEXtreme 11.0 Programming Competition


IEEEXtreme is a global challenge in which teams of IEEE Student members – advised and proctored by an IEEE member, and often supported by an IEEE Student Branch – compete in a 24-hour time span against each other to solve a set of programming problems.

IEEEXtreme 11.0 will take place on
14 October 2017 00:00:00 UTC.

Teams can be composed of up to three collegiate students who are current IEEE student members.

Prizes:

  1. Fame: Unlimited bragging rights and an item for your resume.
  2. Fortune: The Grand Prize is a trip to the IEEE conference of your choice, anywhere in the world.


Ubuntu: How to compile STAN SPG Planning System (http://planning.cis.strath.ac.uk/STAN/) on Ubuntu 11.10

Recently we tried to compile the STAN SPG Planning System (http://planning.cis.strath.ac.uk/STAN/) under Ubuntu 11.10  Oneiric Ocelot which ended up in a failure.

After reviewing the source code of version 3 (http://planning.cis.strath.ac.uk/code/) we found out that there were many changes needed to be done that had to do with the age of the code itself. We believe that with an OS from1999 and the repsective g++ libraries there should be no problem compiling this application but who has one anyway ? (From the README file: “The code has been built and tested using Linux and UNIX (SunOS) with the g++ compiler.” )

Solution:

We realized that most of the errors are pretty much the same ones and had to do with C++ syntax. Following a synopsis of the changes we did:

    • Replaced
      #include <stream.h>

      with

      #include <iostream>
      using namespace std;

      Note on this, be sure to put using namespace std; after the rest of the includes to avoid conflicts and other issues that might arise.

    • Replaced
      #include <stream.h>

      with

      #include <fstream>
    • Replaced
      #include <new.h>

      with

      #include <new>
    • Added
      #include <cstring>
      #include <stdlib.h>

      wherever there was a call for string manipulation like (strcmp(),strlen(),strcpy(),..) or whenever there were commands like exit().

    • Replaced array assignments like:
      exvec = pl.exvec;

      to

      for(int i = 0;i<EXVECSIZE;i++)  {
        exvec[i] = pl.exvec[i];
      };

      The ranges of these arrays we were able to find them from the respective .h files.

    • In the makefile, we changed:
      pddl.yacc.tab.c: alldefs.h pddl.yacc lex.yy.c
          bison pddl.yacc

      to

      pddl.yacc.tab.c: alldefs.h pddl.yacc lex.yy.c
          bison pddl.yacc -o pddl.yacc.tab.c

      Or else the make will fail as it will not find the file pddl.yacc.tab.c.

In the next section you will find all changes we did to the files extensively (Hopefully we did not forget any or mess them up). The format is as follows (the changes do not necessarily imply that all changes should happen at the same place in file):

in <FILE>
line that was changed/deleted
line that was changed/deleted
-
line that was added
line that was added
line that was added
  1. in Makefile
    pddl.yacc.tab.c: alldefs.h pddl.yacc lex.yy.c
    bison pddl.yacc

    pddl.yacc.tab.c: alldefs.h pddl.yacc lex.yy.c
    bison pddl.yacc -o pddl.yacc.tab.c
  2. in BasicTim.h
    #include <stream.h>

    #include <iostream>
    using namespace std; // make sure it goes right after the includes (I believe it affects stdio.h)
  3. in SymTab.cc
    #include <stream.h>

    #include <iostream>
    #include <cstring>
    #include <stdlib.h>
    using namespace std;
  4. in BasicTim.cc
    #include <fstream.h>

    #include <fstream>
  5. in TimInterface.cc
    #include <fstream.h>

    #include <fstream>
  6. in globals.h
    #include <stream.h>
    #include <fstream.h>

    #include <fstream>
    #include <iostream>
    using namespace std;
  7. in stan.h
    #include <stream.h>

    #include <iostream>
    using namespace std;
  8. in facts.h
    #include “stream.h”

    #include <iostream>
    #include <cstring>
    using namespace std;
  9. in facts.cc
    #include <stream.h>

    #include <iostream>
    using namespace std;
  10. in facts.cc
    exvec = pl.exvec;

    for(int i = 0;i<EXVECSIZE;i++) {
    exvec[i] = pl.exvec[i];
    };
  11. in facts.cc
    domination = pl.domination;

    for(int i = 0;i<EXVECSIZE;i++)  {
    domination[i] = pl.domination[i];
    };
  12. in actions.cc
    exvec = pl.exvec;

    for(int i = 0;i<EXVECSIZE;i++)  {
    exvec[i] = pl.exvec[i];
    };
  13. in instantiation.cc
    #include <stream.h>

    #include <iostream>
    using namespace std;
  14. in candidates.h
    #include <stream.h>

    #include <iostream>
    using namespace std;
  15. in main.cc
    #include <stream.h>
    #include <fstream.h>
    #include <new.h>

    #include <iostream>
    #include <fstream>
    #include <new>
    #include <stdlib.h>
    using namespace std;

Soon we will add the modified version of the source code online that should be able to compile by just issuing make stan.


C/C++: Capture stdout from a system() command

	FILE *results;
	int queen;
	if (!(results = popen("./precosat -f nqueens.cnf | tail -n +2 | head -n -1 | tr -d v | tr ' ' '\n' | grep -v '^$' | grep ^[0-9]", "r"))) {
		cout << "Unable to Execute Precosat" << endl << "./precosat -f nqueens.cnf | tail -n +2 | head -n -1 | tr -d v | tr ' ' '\n' | grep -v '^$' | grep ^[0-9]" << endl;
		exit(1);
	}
	for (i = 0; i < queens; i++) {
		fscanf(results,"%d",&queen);
		cout << "Queen #" << i+1 << " goes to [" << ((queen%queens)?(queen%queens):queens) << "]" << endl;
	}
	pclose(results);

Above, you will find an example that was used to extract data from the PrecoSAT SAT Solver in order to solve the N-Queens problem. It returns all positive variables, one per line.

You can see that after the call to popen, it creates a pointer to a file stream that can be used as a regular file to read the data from the called process.


Ubuntu: How to compile PrecoSAT v.570 under ubuntu 11.10

By downloading PrecoSAT from http://fmv.jku.at/precosat/ and trying to install it on Ubuntu 11.10 32-bit (Oneiric Ocelot) by:

    • Decompressing the files
    • and calling ./configure && make

I got the following error at make:

g++ -O3 -m32 -static -Wall -Wextra -DNDEBUG -DNLOGPRECO -DNSTATSPRECO  -c precomain.cc
In file included from precomain.cc:23:0:
precosat.hh:164:31: error: ‘ptrdiff_t’ has not been declared
precosat.hh:270:13: error: ‘ptrdiff_t’ has not been declared
make: *** [precomain.o] Error 1

which can be resolved by adding

#include <cstddef>

at the includes in the file precosat.hh


C: How to tell the status of a socket

If you are trying to check if a socket is empty but you cannot use select(), because what you need is to check the write buffers instead of the read ones just to be sure that you have successfully managed to send all data to your peers before terminating, or if you want to tell if a socket buffer is full.

You can use the ioctl to find out.

To check a write buffer if it empty (assuming you have already put data there and want to check if they were consumed):

ioctl(fd, SIOCOUTQ, &pending);

Where fd is the socket’s file descriptor and pending the variable were the remaining size of data will be returned.

To check a read buffer if it empty (assuming someone has already put data there and you want to check if they there is any without consuming them):

ioctl(fd, SIOCINQ, &pending);
*note the difference on the second parameter, where we change the flag from SIOCOUTQ to SIOCINQ

Among other includes be sure to add these:

#include <sys/ioctl.h>
#include <linux/sockios.h>