DaniWeb Forum Index > Software Development > C++

C++ RSS

unix/C++ segmentation fault

•

Join Date: Jan 2005

Posts: 24

Reputation: crq is an unknown quantity at this point

Solved Threads: 0

crq

Offline

Newbie Poster

unix/C++ segmentation fault

Jan 19th, 2005

hi there. i am new to C++ AND unix. this assignment that i have is really really easy, but the specifics of C++ and getting around in Unix is making it really hard and time consuming. i have a really small program that should be working, but i am getting the wrong output AND at the end of the output i get a Segmentation fault.

i have a function called series that is declared and works fine. i have inserted a cout<< to check that the function is working right. but i am still getting the wrong output AND this error. am i doing something illegal? using the function result as the array index? i know i am not telling you much about the code, i am just wondering if there are any GLARING unix or C++ no-nos that anyone sees.

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
int main (){
   const int MAX_NUM = 60;
 
   const int MAX_CALLS = 41;
 
   int num_calls [MAX_CALLS];
 
   int k = 0;
 
   for(int i=1; i<=MAX_NUM; i++){
      num_calls[i] = 0;
      cout<< series(i) <<endl;
      if ((series (i)) < MAX_CALLS){
        num_calls[series (i)]++;
      }
      else{ 
        k++;
      }
   }
 
   for(int l=1; l<MAX_CALLS; l++){
      cout<< l << "       " << num_calls[l] <<endl;
   }
 
   cout<< "and " << k << "numbers have series length greater than 40" <<endl;
}
int main (){
   const int MAX_NUM = 60;

   const int MAX_CALLS = 41;

   int num_calls [MAX_CALLS];
   
   int k = 0;

   for(int i=1; i<=MAX_NUM; i++){
      num_calls[i] = 0;
      cout<< series(i) <<endl;
      if ((series (i)) < MAX_CALLS){
        num_calls[series (i)]++;
      }
      else{ 
        k++;
      }
   }
   
   for(int l=1; l<MAX_CALLS; l++){
      cout<< l << "       " << num_calls[l] <<endl;
   }
   
   cout<< "and " << k << "numbers have series length greater than 40" <<endl;
}

thanks
crq

•

Join Date: Mar 2004

Posts: 1,620

Reputation: kc0arf is a jewel in the rough

Solved Threads: 50

kc0arf

Offline

Posting Virtuoso

Re: unix/C++ segmentation fault

Jan 19th, 2005

Hi,

First, and this is a style thing... I hate it when people place the brace { on the same line as the expression... just does not look nice to me.

Adjusted:

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
int main ()
{
   const int MAX_NUM = 60;
 
   const int MAX_CALLS = 41;
 
   int num_calls [MAX_CALLS];
 
   int k = 0;
 
   for(int i=1; i<=MAX_NUM; i++)
         {
         num_calls[i] = 0;
         cout<< series(i) <<endl;
         if ((series (i)) < MAX_CALLS)
             {
             num_calls[series (i)]++;
             }
         else
             { 
             k++;
             }
         }
 
   for(int l=1; l<MAX_CALLS; l++)
         {
         cout<< l << "       " << num_calls[l] <<endl;
         }
 
     cout<< "and " << k << "numbers have series length greater than 40" <<endl;
}
int main ()
{
   const int MAX_NUM = 60;

   const int MAX_CALLS = 41;

   int num_calls [MAX_CALLS];
   
   int k = 0;

   for(int i=1; i<=MAX_NUM; i++)
         {
         num_calls[i] = 0;
         cout<< series(i) <<endl;
         if ((series (i)) < MAX_CALLS)
             {
             num_calls[series (i)]++;
             }
         else
             { 
             k++;
             }
         }
   
   for(int l=1; l<MAX_CALLS; l++)
         {
         cout<< l << "       " << num_calls[l] <<endl;
         }
   
     cout<< "and " << k << "numbers have series length greater than 40" <<endl;
}

I notice that you declare main() to be of type INT, and you do not return any number to the OS. I wonder if that is hanging you up.

I would have tried, but you didn't bring along your whole program, and I wasn't about to code it further. I couldn't compile because I had no idea what series is, and at 11:30pm, I am not to creative.

Christian

•

Join Date: Jan 2005

Posts: 24

Reputation: crq is an unknown quantity at this point

Solved Threads: 0

crq

Offline

Newbie Poster

Re: unix/C++ segmentation fault

Jan 19th, 2005

THANKS for the style tips. i agree with you. i like lots of spacing in my coding. however, i have been beaten over the head with doing it the exact opposite ....

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
for(int i=1; i<MAX_CALLS; i++){ h[i]=0} ....
...........
 
.......
for(int i=1; i<MAX_CALLS; i++){ h[i]=0} ....
...........

.......

that stuff makes me crazy, but it seems to be the going style where i am. anything else is a bit "novice" or something ... silly, though it may be.

i think i have figured it out, though. i had some uninitialized array stuff that was making my code not work ... and yes i need to check on the number part. either i left it off when i copied and pasted ... or i lost it somewhere in my coding. i am so new at unix, that i don't know how to go to my file, and open it in the editior. all i know how to do is VIEW the file, copy it. then open a text editor window and paste it in there EVERY time i want to make a change after i compile and run ... ARRRRGGGHHH!!

thanks, though.
crq

•

Join Date: Sep 2004

Posts: 7,540

Reputation: Narue has a reputation beyond repute

Solved Threads: 704

Narue

Offline

Code Goddess

Re: unix/C++ segmentation fault

Jan 19th, 2005

>I hate it when people place the brace { on the same line as the expression
Get over it. Style issues are a matter of opinion, and you shouldn't push your opinions on other people.

>I wonder if that is hanging you up.
That's legal C++. 0 will be returned by default if the compiler supports that feature from the standard. Of course, if Turbo C++ v.old_as_dirt is the OP's compiler, it's undefined behavior.

>cout<< series(i) <<endl;
What is series? Is it a type? Is it a function? Most likely your problem is in the code that you neglected to post.

I'm here to prove you wrong.

•

Join Date: Jan 2005

Posts: 3

Reputation: sykobag is an unknown quantity at this point

Solved Threads: 0

sykobag

Offline

Newbie Poster

Re: unix/C++ segmentation fault

Jan 19th, 2005

In the unix that I used last semester in school the editor was called "pico" just type that on the command line and the text editor comes up. I don't know if that is standard unix or if it was on the server that I was using but you can always give it a shot.

•

Join Date: Jan 2005

Posts: 24

Reputation: crq is an unknown quantity at this point

Solved Threads: 0

crq

Offline

Newbie Poster

Re: unix/C++ segmentation fault

Jan 19th, 2005

thanks for replying!

i actually found the problem ... and it was a goof-up silly mistake. i was doing things in an array element that hadn't been initalized. i am still in java mode it seems (elements of int arrays are by default initalized to 0). somehow that was producing the segmentation fault. i still don't know what that term means, but it turned out to be something silly. i am so unfamiliar with C++ and with Unix that i was sure my mistake was the result of something that i wouldn't know to do.

oh, series is a function. was declared above. i had tested it and i had the problem isolated to 2 lines because of the cout<< calls that i had going.

thanks for the help .. i am sure i will need more in the coming weeks.

thanks
crq

•

Join Date: Jan 2005

Posts: 24

Reputation: crq is an unknown quantity at this point

Solved Threads: 0

crq

Offline

Newbie Poster

Re: unix/C++ segmentation fault

Jan 19th, 2005

•

Originally Posted by sykobag

In the unix that I used last semester in school the editor was called "pico" just type that on the command line and the text editor comes up. I don't know if that is standard unix or if it was on the server that I was using but you can always give it a shot.

hey, sykobag,

i am using pico too. i type pico and a blank window comes up. the problem that i have is this ... when i quit a session, save my file and want to come back to it. if i log back on and type pico, i get a blank editor. how do i call pico for the file that i want to edit instead of calling a blank window each time?

thanks
crq

•

Join Date: Jan 2005

Posts: 3

Reputation: sykobag is an unknown quantity at this point

Solved Threads: 0

sykobag

Offline

Newbie Poster

Re: unix/C++ segmentation fault

Jan 19th, 2005

•

Originally Posted by crq

hey, sykobag,

i am using pico too. i type pico and a blank window comes up. the problem that i have is this ... when i quit a session, save my file and want to come back to it. if i log back on and type pico, i get a blank editor. how do i call pico for the file that i want to edit instead of calling a blank window each time?

thanks
crq

at the bottom of the pico window there should be a load from file or something its been a while since i used it but it will load from a file all of the text you edited before

•

Join Date: Jan 2005

Posts: 24

Reputation: crq is an unknown quantity at this point

Solved Threads: 0

crq

Offline

Newbie Poster

Re: unix/C++ segmentation fault

Jan 19th, 2005

•

Originally Posted by sykobag

at the bottom of the pico window there should be a load from file or something its been a while since i used it but it will load from a file all of the text you edited before

SUPER!! i will try that. it would be a real time saver. i have been copying and pasting and opening and closing ... a real pain.

THANKS!

crq