Seg faults, these are caused by tring to access memory that is not
allocated. (or should i say mallocated hehe :) From visual inspection
it appears that your 1st seg fault is in the following line in
readwants():
fscanf(fp,"%s %d",tmp,&baseball[i].date);
This is because in your main function you declare
ball* baseball;
then you pass baseball into readwants() then you try and access
baseball in readwants() but you never allocated any memory for
baseball... I advise either using malloc() to alloc some memory to
baseball in your main function as follows:
ball* baseball = (ball*)malloc(sizeof(ball) * 50);
Note the I multiply the sizeof(ball) by 50 because that is the length
of the array readwants expects.
OR declaring baseball as an array of length 50 in main. Doing either
one of these things should clear up all the seg faults. Note: I was
not able to test compile the program, but I don't see anything else
off hand.
Let me know if you have any other questions, comments, concerns.
Thanks,
--jld |
Request for Answer Clarification by
derekwtp-ga
on
16 Mar 2003 11:52 PST
sorry . I didnt give you the rest of it, before I do here is my output
now after memory allocation. It still is not giving me the desired
result.
[root@localhost first_p]# ./one
line above readwants
want.names
beginning of readwants function
want.names
1967 134518900
Topps 134518960
baseball 134519020
Killebrew 134519080
this is the end of readlist
struct baseball
{
char name[50];
int date;
int number;
};
typedef struct baseball ball;
some of the file "want.names"
1967 Topps baseball
460 Killebrew
536 Niekro
543 Schneider
546 Woodward
553 Hegan
554 Rodgers
559 Tracewski
562 Blass
567 Hamilton
568 Sullivan
569 Carew
570 Wills
577 Short
578 Boccabella
580 Colavito
585 Bunker
586 Jimenez
590 Richert
593 Westrum
594 Osinski
597 Abernathy
603 Rookies
606 Taylor
607 Stanley
1966 Topps baseball
472 Fox
|
Request for Answer Clarification by
derekwtp-ga
on
16 Mar 2003 16:02 PST
okay. i have gotten around the last time, but I am not sure if even
though i am getting desired output if this is the right way to right
it. My next function is supposed to compare the files so that I can
print a list w/ the updated information. I am supposed to used stacks
and push and pop. do you know where i can find a good reference to use
this in this scenario?
updated main and twofuctions
main()
{
void readwants(ball*,char*);
void readtopps(ball*,char*);
ball* baseball = (ball*)malloc(sizeof(ball) * 1000);
char nambo[50];
int num=4;
strcpy(nambo,"want.names");
printf ("line above readwants\n");
printf ("%s\n",nambo);
readwants(baseball,nambo);
#include<stdio.h>
#include"baseball.h"
void readwants (ball baseball[1000],char fn[])
{
FILE *fp;
char tmp[30];
int i = 0;
printf ("beginning of readwants function\n");
printf ("%s\n",fn);
/* try to open the file */
if(!(fp=fopen(fn,"r"))) {
printf("%s does not exits, starting with empty list\n",fn);
return;
}
while (fscanf(fp,"%s %s",tmp,&baseball[i].number)!=EOF) {
strcpy(baseball[i].name,tmp);
printf ("%s %s \n",&baseball[i].name,&baseball[i].number); ++i; }
fclose(fp);
printf ("this is the end of readlist\n");
}
#include<stdio.h>
#include"baseball.h"
void readtopps (ball baseball[1000],char fn[])
{
FILE *fp;
char tmp[30];
int i = 0;
printf ("beginning of readtopps function\n");
printf ("%s\n",fn);
/* try to open the file */
if(!(fp=fopen(fn,"r"))) {
printf("%s does not exits, starting with empty list\n",fn);
return;
}
while (fscanf(fp," %s ",&baseball[i].number)!=EOF) {
printf ("%s \n",&baseball[i].number); ++i; }
fclose(fp);
printf ("this is the end of readtopps\n");
}
|
Clarification of Answer by
jeanluis-ga
on
16 Mar 2003 16:45 PST
Push and pop are very simple functions, while I dont know a very
*good* reference for these functions you should be able to implement
them with out a problem.
Here is the best reference I could come up with:
"The C Programming Language", 2nd edition, Kernighan and Ritchie
Answer to Exercise 4-5, page 79
http://users.powernet.co.uk/eton/kandr2/krx405.html
In there you can find (very short) push and pop functions, I am sure
you will not have a problem figuring out how they work. For your
functions you can basically use the exact same functions implemented
in the above link, except use ball rather than doubles for your
"stack" (i.e. where they declare double val[MAXVAL]; you would declare
ball val[MAXVAL];)
I hope this helps, but you know the drill, please let me know if you
have any other questions, comments, concerns, etc... :)
Thanks again,
--jld
|
Clarification of Answer by
jeanluis-ga
on
16 Mar 2003 16:47 PST
By the way, so far everything looks good (except your main function
doesn't have a closing brace, but I assume that is a cut+paste
error...)
Thanks
--jld
|
Request for Answer Clarification by
derekwtp-ga
on
17 Mar 2003 11:07 PST
What I am trying to do on this function is compare the two structures
and print out the name and number of only the numbers that appear in
both lists. Ill give you what I have as far as functions starting w/
the one I need help w/
this function is killing me cuz my logic must be wayyyy offff
void compare(Player plays[],Player top[])
{
int x = 0;
int i = 0;
do
{
if (plays[x].cardnum == top[i].cardnum)
{
printf ("%d %s\n",plays[x].cardnum,plays[x].name);
x++;
}
else if (plays[x].cardnum != top[i].cardnum)
{i++;}
}
while (plays[x].cardnum > 0);
}
here is main
main()
{
int readwants(Player*,char*,int);
int readtopps(Player*,char*);
void compare(Player*,Player*);
Player* baseball = (Player*)malloc(sizeof(Player) * 1000);
Player* bigtopps = (Player*)malloc(sizeof(Player) * 1000);
char nambo[50];
char tango[50];
int num = 52;
strcpy(nambo,"want.names");
strcpy(tango,"topps.52");
printf ("line above readwants\n");
printf ("%s\n",nambo);
readwants(baseball,nambo,num);
readtopps(bigtopps,tango);
compare(baseball,bigtopps);
}
#include<stdio.h>
#include"player.h"
int readtopps (Player topps[],char fn[])
{
FILE *fp;
char tmp[30];
int i = 0;
printf ("beginning of readtopps function\n");
printf ("%s\n",fn);
/* try to open the file */
if(!(fp=fopen(fn,"r"))) {
printf("%s does not exits, starting with empty list\n",fn);
return;
}
while (fscanf(fp," %s ",&topps[i].cardnum)!=EOF) {
printf ("%s \n",&topps[i].cardnum); }
fclose(fp);
printf ("this is the end of readtopps\n");
return(i);
}
#include <stdio.h>
#include "player.h"
int readwants(Player* p, char* wantfn, int year)
{
FILE* fp;
char fn[CHARS];
int i=0,wantyear,count;
fp=fopen(wantfn,"r");
/*read first line from want.names*/
fscanf(fp,"%d %*[^\n]%*c",&wantyear);
/* do loop executes until you have read the year of interest */
do{
if (wantyear == year + 1900){
/* this do loop reads the number and name until it finds the
beginning line for the next year */
do{
fscanf(fp,"%d %s ",&p[i].cardnum,p[i].name);
printf ("%d %s \n",p[i].cardnum,p[i].name);
i++;
}while (!feof(fp) && p[i-1].cardnum < 1900);
/* for every year except the last one in the file, you will have
read one line too far, so adjust count if you need to */
if (p[i-1].cardnum > 1900) count=i-1; else count=i;
wantyear= -1;
}else{
/* here is where we go if the year did not match... first
we read a line, then do the while loop to keep reading
until we find another "year" value ie > 1900 */
fscanf(fp,"%d %*[^\n]%*c",&wantyear);
while(wantyear < 1900){
fscanf(fp,"%d %*[^\n]%*c",&wantyear);
}
}
}while(!feof(fp) && wantyear!= -1);
return (count);
}
#define wantfile "want.names"
#define CHARS 80
#define MAX 200
struct PLAYER {
int cardnum;
char name[CHARS];
};
typedef struct PLAYER Player;
here is a copy of the files that will be read from: first is a
topps.xx file
1952 Topps baseball
-------------------
8 10 15 17 20 47 48 49 59 71 136
153 155 159 162 168 170 175 176 186 188 202
215 233 248 252 253 254 257 259 264 270 271 272 274
282 283 284 285 287 293 294 295 297 299 300 308 310 311
312 314 315 316 317 319 320 321 322 323 324 325 327 328 329
330 332 333 334 335 336 338 339 341 342 343 344 345 346
347 348 349 350 351 352 353 354 355 356 357 358 359 360 361
362 363 364 365 366 367 368 370 372 373 374 375 376 377
378 379 380 381 382 383 384 387 388 391 392 393 394
397 398 399 400 401 402 403 405 406 407
second is only a snippet of the want.names for 1952
1952 Topps baseball
4 Lenhardt
8 Marsh
9 Hogue
10 Rosen
11 Rizzuto
14 Elliott
15 Pesky
17 Hegan
20 Loes
22 DiMaggio
34 Valo
36 Hodges
37 Snider
42 Kretlow
47 Jones
48 Page
49 Sain
59 Roberts
66 Roe
71 Upton
72 Olson
74 Hansen
77 Kennedy
86 Gray
98 Pierce
99 Woodling
136 Schmitz
142 Perkowski
146 House
151 Post
152 Evans
153 Rush
154 Muir
155 Overmire
159 Rogovin
162 Crandall
166 LaPalme
168 Silvera
169 Judson
170 Bell
173 Smalley
175 Martin
176 Edwards
182 Hitchcock
184 Ramazzotti
186 Masterson
188 Podbielan
190 Johnson
192 Ginsberg
197 Strickland
199 Zuverink
202 Collins
205 King
215 Bauer
216 Ashburn
222 Evers
223 Ennis
227 Garagiola
230 Batts
233 Friend
237 Coleman
242 Poholsky
243 Doby
244 Wertz
247 Gumpert
248 Shea
250 Erskine
252 Bickford
253 Berardino
254 Dobson
256 Suder
257 Avila
258 Gromek
259 Addis
264 Hartsfield
267 Gordon
268 Lemon
269 Nixon
270 Brissie
271 Selsing
272 Garcia
273 Palica
274 Branca
276 Wilson
277 Wynn
279 Stewart
280 Boyer
281 Brown
282 Tebbetts
283 Masi
284 Arft
285 Fannnin
286 DeMaestri
287 Bilko
288 Nichols
289 Holmes
293 Sisti
294 Cooper
295 Caverretta
296 Rolfe
297 Seminick
299 Murray
300 McCosky
301 Porterfiel
302 Surkont
303 Dorish
304 Dente
305 Richards
307 Campos
308 Aloma
309 Busby
310 Metkovich
311 Mantle
312 Robinson
|
Clarification of Answer by
jeanluis-ga
on
17 Mar 2003 12:23 PST
Ok I dont have much time right now but I can give you a few quick
pointers, and I can come back later on tonight with more details I
hope that is ok.
Ok the 1st thing I would do is in your readtopps() function read the
cardnum as an integer (it is not a string)
Next: As you read in each file keep track of the number of entries you
read. Then use the number of entries in each file in the compare
function to setup some nested for loops as follows:
for (x = 0; x < num_in_wants_file; x++) {
for (i = 0; i < num_in_topps_file; i++) {
}
}
Inside that nested loop all you have to do is compare the cardnum of
the topps and the wants and if they are the same then you have a hit.
:)
If you have any other Q's let me know
thanks --jld
|
Request for Answer Clarification by
derekwtp-ga
on
17 Mar 2003 12:45 PST
When I change the string to an integer I get output like:
136784800
136784884
136784968
136785052
136785136
136785220
136785304
136785388
136785472
136785556
136785640
136785724
136785808
136785892
136785976
136786060
136786144
136786228
136786312
136786396
136786480
136786564
136786648
while (fscanf(fp,"%i",&topps[i].cardnum)!=EOF) {
printf ("%i \n",&topps[i].cardnum);++i; }
That is why i used %string. it never showed invalid output
|
Clarification of Answer by
jeanluis-ga
on
17 Mar 2003 13:34 PST
That is because in your printf statement you are printing the address
of cardnum... You want to print the contents of cardnum...
That means remove the & when you print the cardnum as an integer... :)
Let me know if you have any other questions, comments, concerns.
Thanks,
--jld
|
Request for Answer Clarification by
derekwtp-ga
on
17 Mar 2003 16:56 PST
sorry I meant to show you this output. Dont want you to think i dont t/shoot : )
beginning of readtopps function
topps.52
1952
0
0
0
0
0
0
0
0
0
and here is my function
while (fscanf(fp,"%d",&topps[i].cardnum)!=EOF) {
printf ("%d \n",topps[i].cardnum);++i; }
Also could you explain you explaination above w/ the embedded for loop?
-Derek
|
Clarification of Answer by
jeanluis-ga
on
18 Mar 2003 05:13 PST
The readtopps function you have now, gets all messed up with the
"header" (1952 Topps baseball). the function works perfectly for me
when I remove that line from the file, but produces the output you
described when I put the header back in...
So what you should do is read the 1st line in first, then read the
contents of the file with the loop you currently have.
And for the compare() function you want to do something like this:
for (x = 0; x < num_in_wants_file; x++) {
for (i = 0; i < num_in_topps_file; i++) {
if (??? == ???) {
printf("%i %s\n", ???.cardnum, ???.name);
}
}
}
Where you loop through each cardnum in the wants array, with each
cardnum in the topps array. When they are equal then you record the
cardnum and name. (i.e. print them out) Above I provided an outline of
what the loop should look like, that will print a list of numbers and
names of people in both topps and wants... Which now that I have gone
back and re-read the assignment I am not sure that is what your prof
is looking for. Does he want a list of people that are in both files?
Or a list of people that are in wants but not in topps? If he wants
the latter then you can use very similar logic to what I have above,
but you must change it a bit to weed out the names in the wants list.I
will let you work on this for a little while, and see how far you can
get... If you need more help let me know... Also please clarify
exactly what the results are supposed to be, Thanks,
--jld
|
Request for Answer Clarification by
derekwtp-ga
on
18 Mar 2003 06:27 PST
He is looking for the list of people that are on both lists, printed
to standard output by name and number since only one list has the
names. I am reading the rest of you reply now. thanks. I know the
drill : )
|
Request for Answer Clarification by
derekwtp-ga
on
18 Mar 2003 13:11 PST
Looking at the format, do you understand why this is saying "parse
error before fclose?"
#include<stdio.h>
#include"player.h"
int readtopps (Player topps[],char fn[])
{
FILE *fp;
char temp[30];
int i = 0;
printf ("beginning of readtopps function\n");
printf ("%s\n",fn);
/* try to open the file */
if(!(fp=fopen(fn,"r"))) {
printf("%s does not exits, starting with empty list\n",fn);
return;}
fscanf (fp,"%s %s %s",&temp,&temp,&temp);
fscanf (fp,"%s %s %s",&temp,&temp,&temp);
do{(fscanf(fp,"%d",&topps[i].cardnum)!=EOF);
printf("%d \n",topps[i].cardnum);++i; }
fclose(fp);
printf("this is the end of readtopps\n");
return(i);
}
|
Clarification of Answer by
jeanluis-ga
on
18 Mar 2003 13:41 PST
Because you need a semicolon after:
printf("%d \n",topps[i].cardnum);++i; }
Typically parse errors are caused by missing semicolons, or
miss-matched braces, or something like that... Whenever you see a
generic syntax or parse error message from your compiler you should
always check your semicolons, braces, spelling and stuff like that in
the lines just before the error is reported.
Let me know if you have any other questions, comments, concerns.
Thanks,
--jld
|
Clarification of Answer by
jeanluis-ga
on
18 Mar 2003 13:57 PST
Whoops: your do loop is not formatted correctly what you want is
something more like this:
while (fscanf(fp,"%d",&topps[i].cardnum)!=EOF) {
}
Sorry about that last comment, I was in a rush, and I didn't have time
to really look at the code. Then I went back and did a double take and
noticed that I was totally wrong and way off base.. :)
fewf.. This is a good time to mention coding style, most people
adhear to some kind of coding style that makes the code easy to read.
Some simple rules to follow are: All code in the same scope is
indented to the same level. Closing braces are on a newline. One
semicolon per line. Just things like that to make the code easier to
read. :)
Thanks,
--jld
|
Request for Answer Clarification by
derekwtp-ga
on
18 Mar 2003 17:46 PST
Jean, this still does not get the required result. any ideas?
int readtopps (Player topps[],char fn[])
{
FILE *fp;
char temp[30];
int i = 0;
printf ("beginning of readtopps function\n");
printf ("%s\n",fn);
/* try to open the file */
if(!(fp=fopen(fn,"r"))) {
printf("%s does not exits, starting with empty list\n",fn);
return;}
fscanf (fp,"%s",&temp);
fscanf (fp,"%s",&temp);
while (fscanf(fp,"%d",&topps[i].cardnum)!=EOF)
{printf("%d \n",topps[i].cardnum); ++i; }
fclose(fp);
printf("this is the end of readtopps\n");
return(i);
}
|
Clarification of Answer by
jeanluis-ga
on
18 Mar 2003 19:28 PST
Well it is still the same problem as before really... The header is
messing the function up... You added 2 fscanfs but they only read in
the next word on the input stream. So when you do this:
fscanf (fp,"%s",&temp);
fscanf (fp,"%s",&temp);
What you are reading is 1952 in the 1st fscanf, and Topps in the
second fscanf... When what you want is to read in everything up to the
newline. To do this you might want to consider replacing the fscanfs
with fgets() calls...
Here is a link to the docs for fgets:
"Stdio: fgets"
http://www.cplusplus.com/ref/cstdio/fgets.html
As you can see fgets reads upto the number of chars you specify, or
until a newline, which would make it ideal for this situation. :)
Thanks again,
--jld
|
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