file i/o dilemma

okay so i am now writing code for an assignment where i have to write to a binary file a report for a teacher to use for a class where it will write to the file in this format:

idNumber Name gender classlvl ProgrammingScores TestScores
111111111 last, first M 11 00 00 00 00 00 00

for any amount of students and with the only thing is that i can only use 44 bytes per student meaning a stucture with members all type char.....

the other thing is that i have to have each function on it's own file, so making a header file and compiling the .o files of the functions with the main function that will be using the functions to do things....

my problem is so far with the deleting and adding scores....now i was wondering if there was a simple way to just call a function that could help me to find the student by id number and append one of the three scores???

also i have the problem of having to once i find the data freeing it well that is easy just make an array and once i find a match just freading it to a tmp pointer and then freeing it..the problem is that is there also a way to find the student by idnumber so i can call free()???

if not i will have to read to an array manipulate that array to either delete and then write over...but that seems to time consuming...and probably slow utilizing more resources to make it happen...

same for the scores should i just read to an array the file and then manipulate just the scores and then write them back???

but without knowing the end of the file i would most likely get an error because it is difficult to manipulate a binary file in such way...

any suggestion would help sorry i don't have any plausible source code since most of my source code right now is being converted to the more complex way of having multiple loops where it will read to an array, then manipulate the array, and then rewrite the students back to the file...

A file with fixed-length records is essentially an array, where the [ ] operator is replaced by calls to fseek().

So if you have a way of turning a student ID into a record number, so you can do seeks to 44*RecNum, then you can achieve that.

Also like an array, you can't just delete things in the middle, and have all the following data shuffle down one place automatically. As you say, this could be expensive. Actual databases reserve a unique pattern which means "deleted data". Perhaps using student 999999999 for this purpose.

> my source code right now is being converted to the more complex way of having multiple loops
Try making it simpler first. If you're thinking it's hard to write now, just wait until you try to debug it.

okay so your like saying do this:

while(!eofe(file_ptr)){ <--to make sure doesn't seek beyond the limit of written data
then use fseek to set to to beginning of file with SEEK_(whatever it is..)

then will have to read at that exact position using ftell() then will have to check if not won't delete else free at ftell() then check and make everything move up!!!

thanks for the help i was just writing down to much code and trying to modulize everything!!!

okay finally got some source code to show i still am having some issues with arrays and pointers...but this is as far as i have got...

student.h (aka header file)

Code:

---

#include <stdio.h>
#include <stdlib.h>
#define FILE_NAME "~/CSC60/lab5/out.txt"
#define MAX_SIZE 29
#define SCORE_TEST 3
#define SCORE_PROGRAM 5
#define ID 9
#define SIZE 3

typedef struct the_student {
        char idNumber[ID], name[MAX_SIZE], gender,
        classLvl, age[SIZE], testScore[SCORE_TEST],
        programScore[SCORE_PROGRAM];
}student;

void addStudent();

void deleteStudent(char[], int);

void addTestScore(char[], int);

void addProgramScore(char[], int);

void outputClassReport();

---

test.c (aka the main method)

Code:

---

#include <stdio.h>
#include <stdlib.h>
#include "student.h"

int main(){
        int num, quit = 0;
        char id [];
        while(quit != 6){
                printf("Please enter the number of the option you wish to run:\n");
                printf("1. add student\n2. delete student\n3. add test score\n");
                printf("4. add program score\n5. output class status\n 6. quit\n");
                scanf("&#37;d\n", &num);
                switch(num){
                        case 1: addStudent();
                                break;
                        case 2: printf("Please enter the 9-digit idNumber of the student");
                                scanf("%s" &id);
                                deleteStudent(id, sizeof(id));
                                break;
                        case 3: printf("Please enter the 9-digit idNumber of the student");
                                scanf("%s" &id);
                                addTestScore(id, sizeof(id));
                                break;
                        case 4: printf("Please enter the 9-digit idNumber of the student");
                                scanf("%s" &id);
                                addProgramScore(id, sizeof(id));
                                break;
                        case 5: outputClassReport();
                                break;
                        case 6: quit = 6;
                                break;
                }//end switch statement
        }//end while loop
        return 0;
}//end main

---

addP.c (aka adding students with no scores)

Code:

---

#include <stdio.h>
#include <stdlib.h>
#include "student.h"

void addProgramScore(char id[], int size){
        int found =0, i=0,z=0, pos=0;
        char chars[SCORE_PROGRAM];
        FILE* FILE_PTR;
        FILE_PTR = fopen(FILE_NAME, "rb+");
        fseek(FILE_PTR, 0, SEEK_END);
        pos = ftell(FILE_PTR);
        rewind(FILE_PTR);
        student *tmp, array[pos];
        tmp = malloc(sizeof(student));
        tmp->idNumber = id;
        fread(array, sizeof(student), pos, FILE_PTR);
        printf("What number Program score do you wish to enter: ");
        scanf("%d", &z);
        printf("What is score you are inputing to program score number %d :" &z);
        scanf("%s\n", chars);
        for(i =0; i<pos; i++){
                if(array[i]->idNumber == tmp->idNumber){
                        array[i]->programScore[z] = chars;
                }//end if statement
        }//end for loop
        fclose(FILE_PTR);
}//end deleteStudent

---

delete.c (aka deleting students)

Code:

---

#include <stdio.h>
#include <stdlib.h>
#include "student.h"

void deleteStudent(char num[], int size){
        FILE* FILE_PTR;
        int found = 0, pos, i=0, z=0;
        student *find;
        FILE_PTR = fopen(FILE_NAME, "ab+");
        find = malloc(sizeof(student));
        find->idNumber = num;
        fseek(FILE_PTR, 0, SEEK_END);
        pos = ftell(FILE_PTR);
        rewind(FILE_PTR);
        student array[pos];
        fread(array, sizeof(student), pos, FILE_PTR);
        while(z++ < pos){
                if(array[z]->idNumber == find->idNumber){
                        for(i=z; i< pos; i++){
                                array[z] = array[z+1];
                        }//end for loop
                }//end if statement
                fseek(FILE_PTR, 1, SEEK_CUR);
        }//end while loop
        fclose(FILE_PTR);
}//end deleteStudent

---

addT.c (aka adding test scores to students by idnumber)

Code:

---

#include <stdio.h>
#include <stdlib.h>
#include "student.h"

void addTestScore(char *id[], int size){
        int found =0, i=0,z=0, pos;
        char chars[SCORE_TEST];
        FILE *FILE_PTR;
        FILE_PTR = fopen(FILE_NAME, "rb+");
        fseek(FILE_PTR, 0, SEEK_END);
        pos = ftell(FILE_PTR);
        rewind(FILE_PTR);
        student *tmp, *array[pos];
        tmp = malloc(sizeof(student));
        tmp->idNumber = id;
        fread(array, sizeof(student), pos, FILE_PTR);
        printf("What number Test score do you wish to enter: ");
        scanf("%d", &z);
        printf("What is score you are inputing to test score number %d :", &z);
        scanf("%s", chars);
        for(i =0; i<pos; i++){
                if(array[i]->idNumber == tmp->idNumber){
                        array[i]->testScore[z] = chars;
                }//end if statement
        }//end for loop
        fclose(FILE_PTR);
}//end addTestScores

---

addP.c (same as above except dealing with program scores instead)

Code:

---

#include <stdio.h>
#include <stdlib.h>
#include "student.h"

void addProgramScore(char id[], int size){
        int found =0, i=0,z=0, pos=0;
        char chars[SCORE_PROGRAM];
        FILE* FILE_PTR;
        FILE_PTR = fopen(FILE_NAME, "rb+");
        fseek(FILE_PTR, 0, SEEK_END);
        pos = ftell(FILE_PTR);
        rewind(FILE_PTR);
        student *tmp, array[pos];
        tmp = malloc(sizeof(student));
        tmp->idNumber = id;
        fread(array, sizeof(student), pos, FILE_PTR);
        printf("What number Program score do you wish to enter: ");
        scanf("%d", &z);
        printf("What is score you are inputing to program score number %d :" &z);
        scanf("%s\n", chars);
        for(i =0; i<pos; i++){
                if(array[i]->idNumber == tmp->idNumber){
                        array[i]->programScore[z] = chars;
                }//end if statement
        }//end for loop
        fclose(FILE_PTR);
}//end addProgramScore

---

outputC.c (aka printing out the report card)

Code:

---

#include <stdio.h>
#include <stdlib.h>
#include "student.h"

void outputClassReport(){
        int pos, i;
        FILE *FILE_PTR;
        FILE_PTR = fopen(FILE_NAME, "rb");
        student *tmp;
        tmp = malloc(sizeof(student));
        fseek(FILE_PTR, 0, SEEK_END);
        pos = ftell(FILE_PTR);
        student array[pos];
        rewind(FILE_PTR);
        fread(array, sizeof(student), pos, FILE_PTR);
        printf("\t\t\tCLASS \t\t TEST");
        printf("\tID \t NAME  \t LVL  GENDER  AGE  SCORES \t PROGRAM SCORES");
        printf("----------------------------------------------------------------------------");
        for(i=0; i<pos; i++)
                printf("%9s %s %5s %2s %4s %2s %2s", array[i]->idNumber, array[i]->name,
                        array[i]->classLvl, array[i]->gender,array[i]->age, array[i]->testScore,
                        array[i]->programScore);
        }//end while loop
        fclose(FILE_PTR);
}//end outputClassReport

---

okay so i have fixed alot of errors in my code and it is much better, but i have seemed to stumble upon an error i cannot figure out maybe one of you could be of more assistance than me just starring at it all day.

here is the script file showing the error...

Code:

---

Script started on Sun 09 Nov 2008 11:33:41 AM PST
> gcc -c addS.c addT.c addP.c deleteS.c outputC.c
> gcc -g *.o test.c
addS.o(.text+0x6d): In function `addStudent':
: warning: the `gets' function is dangerous and should not be used.
> gdb a.out
GNU gdb Red Hat Linux (6.3.0.0-1.159.el4rh)
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i386-redhat-linux-gnu"...Using host libthread_db library "/lib/tls/i686/nosegneg/libthread_db.so.1".

(gdb) run a.out
Starting program: /gaia/class/student/thronej/CSC60/lab5/a.out a.out
Please enter the number of the option you wish to run:
1. add student
2. delete student
3. add test score
4. add program score
5. output class status
6. quit
1
Please enter their 9-digit id number: 11111111

Program received signal SIGSEGV, Segmentation fault.
0x00c16156 in _IO_vfscanf_internal () from /lib/tls/i686/nosegneg/libc.so.6
(gdb) where
#0  0x00c16156 in _IO_vfscanf_internal () from /lib/tls/i686/nosegneg/libc.so.6
#1  0x00c1c6e6 in scanf () from /lib/tls/i686/nosegneg/libc.so.6
#2  0x080487bc in addStudent ()
#3  0x08048dad in main () at test.c:12
(gdb) frame 2
#2  0x080487bc in addStudent ()
(gdb) x/i 0x080487bc
0x80487bc <addStudent+56>:      add    $0x10,%esp
(gdb) quit
The program is running.  Exit anyway? (y or n) y
> exit
exit

Script done on Sun 09 Nov 2008 11:35:29 AM PST

---

here is the main method that is used to call the functions:

Code:

---


#include <stdio.h>
#include <stdlib.h>
#include "student.h"

int main(){
        int num = 0, id = 0;
        while(1){
                printf("Please enter the number of the option you wish to run:\n"
                      "1. add student\n2. delete student\n3. add test score\n"
                      "4. add program score\n5. output class status\n6. quit\n");
                scanf("%d", &num);
                if(num == 1){addStudent();}
                else if(num == 2){
                        printf("Please enter the 9-digit idNumber of the student");
                        scanf("%d\n", &id);
                        deleteStudent(id);
                }//end elseif statement
                else if(num == 3){
                        printf("Please enter the 9-digit idNumber of the student");
                        scanf("%d\n", &id);
                        addTestScore(id);
                }//end else if statement
                else if(num == 4){
                        printf("Please enter the 9-digit idNumber of the student");
                        scanf("%d\n", &id);
                        addProgramScore(id);
                }//end else if statement
                else if(num == 5){outputClassReport();}
                else{
                        return 0;
                }//end else statement
        }//end while loop
        return 0;
}//end main

---

here is the revised add student function...

Code:

---

#include <stdio.h>
#include <stdlib.h>
#include "student.h"

void addStudent(){
        student *tmp;
        tmp = (student *)malloc(sizeof(student));
        rec r;
        char tmper, dummy[80];
        FILE *FILE_PTR;
        printf("Please enter their 9-digit id number: ");
        scanf("%d", tmp->idNumber); //here is where it will error
        printf("\nPlease enter their name: ");
        fgets(dummy, sizeof(dummy), stdin);
        gets(tmp->name);
        printf("\nPlease enter their class level: ");
        fgets(dummy, sizeof(dummy), stdin);
        scanf("%c", &tmper);
        r.classLvl = tmper;
        printf("\nPlease enter their gender: ");
        scanf("%c", &tmper);
        r.gender = tmper;
        tmp->cLvl_gender = r.gender;
        tmp->cLvl_gender = r.classLvl;
        printf("\nPlease enter their age: ");
        scanf("%c", tmp->age);
        FILE_PTR = fopen(FILE_NAME, "ab+");
        fwrite(tmp, sizeof(tmp), 1, FILE_PTR);
        fclose(FILE_PTR);
}//end addStudent

---

here is the header file student.h

Code:

---

#include <stdio.h>
#include <stdlib.h>
#define FILE_NAME "~/CSC60/lab5/out.txt"
#define MAX_SIZE 29
#define SIZE 3

typedef struct {
        int idNumber;
        char name[MAX_SIZE],testScore[SIZE], programScore[SIZE];
        char cLvl_gender, age;
}student;

typedef struct {
        unsigned int classLvl : 3;
        unsigned char gender : 1;
        unsigned : 4;
} rec;

void addStudent();

void deleteStudent(int);

void addTestScore(int);

void addProgramScore(int);

void outputClassReport();

---

Try
gcc -W -Wall -ansi -pedantic -c addS.c addT.c addP.c deleteS.c outputC.c

It will (amongst other things) tell you that the scanf line in question is NOT a pointer to an int, as is expected.

here is the code i get from addS.c:

Code:

---

In file included from addS.c:3:
student.h:15: warning: type of bit-field `gender' is a GCC extension
addS.c: In function `addStudent':
addS.c:8: warning: ISO C90 forbids mixed declarations and code
addS.c:10: warning: ISO C90 forbids mixed declarations and code
addS.c: At top level:
addS.c:31: error: syntax error before '/' token

---

i don't understand the error ISO C90 forbids mixed declarations and code... the line 8 points to where i say: rec *r;

here is a newer revised edition of addS.c I have got rid of some of the errors but as you can tell the others i don't understand them.

Code:

---

#include <stdio.h>
#include <stdlib.h>
#include "student.h"

void addStudent(){
        student *tmp;
        tmp = (student *)malloc(sizeof(student));
        rec *r;
        r = (rec *)malloc (sizeof(rec));
        char tmper, dummy[80];
        FILE *FILE_PTR;
        printf("Please enter their 9-digit id number: ");
        scanf("%d", &tmp->idNumber);
        printf("\nPlease enter their name: ");
        fgets(dummy, sizeof(dummy), stdin);
        gets(tmp->name);
        printf("\nPlease enter their class level: ");
        fgets(dummy, sizeof(dummy), stdin);
        scanf("%c", &tmper);
        r->classLvl = tmper;
        printf("\nPlease enter their gender: ");
        scanf("%c", &tmper);
        r->gender = tmper;
        tmp->cLvl_gender = r->classLvl;
        tmp->cLvl_gender = r->gender;
        printf("\nPlease enter their age: ");
        scanf("%c", &tmp->age);
        FILE_PTR = fopen(FILE_NAME, "ab+");
        fwrite(tmp, sizeof(tmp), 1, FILE_PTR);
        fclose(FILE_PTR);
}//end addStudent

---

It means just what it says -- in ISO C90, you can't mix declarations with code. All variables must appear at the beginning -- once you do a line of code, like say

Code:

---

tmp = (student *)malloc(sizeof(student));

---

no more variables. There also aren't //-style comments in ISO C90.

Quote:

---

#define SCORE_TEST 3
#define SCORE_PROGRAM 5
#define ID 9
#define SIZE 3

---

I'm not sure why you're using CHARS where unsigned INTS and DWORDS would do ?

> student.h:15: warning: type of bit-field `gender' is a GCC extension
bit-fields are always 'int' or 'unsigned int', regardless of how many actual bits you've assigned to the field.

Is the code working any better now?

Further, why are you using bitfields in the first place? Unless you are writing code for something significantly smaller than a mobile phone AND you have thousands of these student records to store in your little device, the saving in memory is definitely not worth it (and if you have less than quite many (a few dozen or more) of the student records, you proably loose out on the code taking up more space, compared to the saving in space the field takes).

--
Mats

i have to make every structure under 44bytes!!!

that is why i try to get the smallest allowed type to each variable without getting any overflow errors...

idNumber can be up to 9 digits...name can be a string of up to 29 characters...

age is 100 or less, class level is only...

i will used unsigned ints instead of ints and unsigned chars instead of chars i figured that it will be less space but besides that everything else is there so i don't go over the allowed size of the student structure...

i am also getting rid of the rec structure and putting it into the student structure as another member...

signed ints and unsigned ints take up the same storage only difference is that for a signed object the MSB is used for the sign bit.
same goes for signed chars and unsigned chars.

9 digits: int = 4 bytes.
29 characters = 30 bytes
age: char = 1 byte.
That's a total of 35 bytes. What do you have to fill the next 9 bytes with?

Unsigned or signed integers take up exactly the same amount of space - the only diference is what branch instructions the compiler generates for >, <, >=, <= operators.

Bitfields, unless they are packed together in a bunch, will take a byte anyways.

--
Mats

Quote:

---

Originally Posted by matsp

9 digits: int = 4 bytes.
29 characters = 30 bytes
age: char = 1 byte.
That's a total of 35 bytes. What do you have to fill the next 9 bytes with?

---

Looks like gender, class level, test score, and program score -- three chars and an int for seven bytes (assuming test score doesn't get over 255). Still two bytes to spare.

Code:

---

#include <stdio.h>
#include <stdlib.h>
#define FILE_NAME "~/CSC60/lab5/out.txt"
#define MAX_SIZE 29
#define SIZE 3

typedef struct {
        int idNumber;
        char name[MAX_SIZE],testScore[SIZE], programScore[SIZE];
        char cLvl_gender, age;
}student;

---

imho i count 41 bytes based on the struct declaration above so you sure have some bits leftover.

okay well i made them all unsigned ints but i am having issues with the fwrite statement:

Code:

---

#include <stdio.h>
#include <stdlib.h>
#include "student.h"

void addStudent(){
        student tmp;
        char tmper, dummy[80];
        FILE *FILE_PTR;
        FILE_PTR = fopen(FILE_NAME,"ab+");
        printf("Please enter their 9-digit id number: ");
        scanf("%d", &tmp.idNumber);
        printf("\nPlease enter their name: ");
        fgets(dummy, sizeof(dummy), stdin);
        gets(tmp.name);
        printf("\nPlease enter their class level: ");
        fgets(dummy, sizeof(dummy), stdin);
        scanf("%c", &tmper);
        tmp.classLvl = tmper;
        printf("\nPlease enter their gender: ");
        scanf("%c", &tmper);
        tmp.gender = tmper;
        printf("\nPlease enter their age: ");
        scanf("%d", &tmp.age);
        fwrite(&tmp, sizeof(student), 1, FILE_PTR);//error's here
        fclose(FILE_PTR);
}//end addStudent

---

and here is the revised header file:

Code:

---

#include <stdio.h>
#include <stdlib.h>
#define FILE_NAME "~/CSC60/lab5/out.txt"
#define MAX_SIZE 29
#define SIZE 3

typedef struct {
        unsigned int idNumber;
        unsigned char name[MAX_SIZE],testScore[SIZE], programScore[SIZE];
        unsigned char age;
        unsigned int classLvl : 3, gender : 1;
}student;

void addStudent();

void deleteStudent(unsigned int);

void addTestScore(unsigned int);

void addProgramScore(unsigned int);

void outputClassReport();

---

it seems to not like my fwrite line i tried it both with a pointer and with a regular struc assignment and not a structure pointer and it will all error on this line..

Quote:

---

Originally Posted by adramalech

okay well i made them all unsigned ints but i am having issues with the fwrite statement:

Code:

---

#include <stdio.h>
#include <stdlib.h>
#include "student.h"

void addStudent(){
        student tmp;
        char tmper, dummy[80];
        FILE *FILE_PTR;
        FILE_PTR = fopen(FILE_NAME,"ab+");
        printf("Please enter their 9-digit id number: ");
        scanf("%d", &tmp.idNumber);
        printf("\nPlease enter their name: ");
        fgets(dummy, sizeof(dummy), stdin);
        gets(tmp.name);
        printf("\nPlease enter their class level: ");
        fgets(dummy, sizeof(dummy), stdin);
        scanf("%c", &tmper);
        tmp.classLvl = tmper;
        printf("\nPlease enter their gender: ");
        scanf("%c", &tmper);
        tmp.gender = tmper;
        printf("\nPlease enter their age: ");
        scanf("%d", &tmp.age);
        fwrite(&tmp, sizeof(student), 1, FILE_PTR);//error's here
        fclose(FILE_PTR);
}//end addStudent

---

and here is the revised header file:

Code:

---

#include <stdio.h>
#include <stdlib.h>
#define FILE_NAME "~/CSC60/lab5/out.txt"
#define MAX_SIZE 29
#define SIZE 3

typedef struct {
        unsigned int idNumber;
        unsigned char name[MAX_SIZE],testScore[SIZE], programScore[SIZE];
        unsigned char age;
        unsigned int classLvl : 3, gender : 1;
}student;

void addStudent();

void deleteStudent(unsigned int);

void addTestScore(unsigned int);

void addProgramScore(unsigned int);

void outputClassReport();

---

it seems to not like my fwrite line i tried it both with a pointer and with a regular struc assignment and not a structure pointer and it will all error on this line..

---

What's wrong with it -- or at least what does your compiler think is wrong with it, or whatever.

Exactly what error do you get?

I hacked your code around a bit to remove the // comments, not use bitfields.

Using this:

Code:

---


typedef struct {
        unsigned int idNumber;
        unsigned char age;
        unsigned char classLvl, gender;
        char name[MAX_SIZE],testScore[SIZE], programScore[SIZE];
}student;

---

takes exactly 44 bytes (using gcc-mingw 3.4.x). No need for bitfields.

However, to store age in a byte, you need a temporary variable for scanf, otherwise the scanf will store the data in the wrong place (because scanf assumes that you give it the right arguemnts - but an unsigned char is only 1 byte, a unsigned long is 4 bytes, so it will overwrite 3 bytes of whatever is after that field.

thanks for the clarification i was confused that i would need to use a bitfield operations to make sure it has the right size.

the error i get is this: 0x00c1fc38 in fwrite () from /lib/tls/i686/nosegneg/libc.so.6

maybe it has to do with the bitfield problem???

The bitfields are not part of the struct student but are part of the struct rec.
Trace the call stack; compile with -g0 and do a bt in gdb and post it here.

it has nothing to do with bitfield operations as i have tried both ways and none of them seem to make anything different in the error same thing....

What platform are you on? Maybe you have an older or bad version of the libc shared library.

okay so i still have the error from the fwrite i found out it wasn't the student structure that i was writing to it but more the file stream wasn't substantiated i even tried to open the binary file in the main method just to substantiated it....using this:

Code:

---

FILE *FILE_PTR;
FILE_PTR = fopen(FILE_NAME, "wb+");
if(FILE_PTR == NULL){perror("File stream was not opened!"); return 0;}
fclose(FILE_PTR);

---

those were the four lines before i even started anything...the FILE_NAME variable is substantiated as FILE_NAME = "~CSC60/lab5/out"; in the header file...

here is the gcc -v output:

Code:

---

> gcc -v
Reading specs from /usr/lib/gcc/i386-redhat-linux/3.4.6/specs
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --enable-shared --enable-threads=posix --disable-checking --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-java-awt=gtk --host=i386-redhat-linux
Thread model: posix
gcc version 3.4.6 20060404 (Red Hat 3.4.6-10)

---

Code:

---

Script started on Mon 10 Nov 2008 06:50:50 PM PST
> ls
addP.c  addS.c]  addT.o    deleteS.o  outputC.o  test.c
addP.o  addS.o  a.out*    Makefile*  script    typescript
addS.c  addT.c  deleteS.c  outputC.c  student.h
> gdb a.out
GNU gdb Red Hat Linux (6.3.0.0-1.159.el4rh)
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i386-redhat-linux-gnu"...Using host libthread_db library "/lib/tls/i686/nosegneg/libthread_db.so.1".

(gdb) run a.out

Starting program: /gaia/class/student/thronej/CSC60/lab5/a.out a.out
Please enter the number of the option you wish to run:
1. add student
2. delete student
3. add test score
4. add program score
5. output class status
6. quit
1
Didn't open file!: No such file or directory
Please enter their 9-digit id number: 1111

Please enter their name: aijowfaiowjf

Please enter their class level: 11

Please enter their gender: m

Please enter their age: 21

Program received signal SIGSEGV, Segmentation fault.
0x00c1fc38 in fwrite () from /lib/tls/i686/nosegneg/libc.so.6
(gdb) bt
#0  0x00c1fc38 in fwrite () from /lib/tls/i686/nosegneg/libc.so.6
#1  0x080488e2 in addStudent () at addS.c:27
#2  0x08048d7d in main () at test.c:16
(gdb) fr 1
#1  0x080488e2 in addStudent () at addS.c:27
27              fwrite(&tmp, sizeof(student), 1, FILE_PTR);
(gdb) quit
The program is running.  Exit anyway? (y or n) y
> exit
exit

Script done on Mon 10 Nov 2008 06:51:31 PM PST

---

the only thing i switched in addS.c was putting the fopen at the top and then just adding in perror to catch the non-opening of the stream...

I'm not completely convinced that ~ is interpreted in the C library. Leave out the path, since it's the same path you're running in, and see what happens.

In the filename component if "CSC60" is not the username the tilde in "~CSC60/lab5/out" will not expand to the full pathname of the file.
Replace the symbolic constant with the complete pathname to the output file and then run your program as in

Code:

---

#define FILE_NAME "/home/username/lab/CSC60/lab5/out.txt"

---

use code tags well and don't post long run-on lines as it's very hard on the eyes.

> FILE_PTR = fopen(FILE_NAME,"ab+");
Always check your errors.

Had you done a test such as this
if ( FILE_PTR == NULL )

you would have seen a specific problem, rather than some random looking crash.

okay that seemed to be my issue i just made the file name now just "out" because it ignores the .txt extention and will write to the binary file

my issue is now making sure that i correctly output the structure and that it can do the other function correctly

i thank everyone for there help and response ....without finishing this i would never have been able to do anything else....