Hello
i have a little problem,i am making a phone book with linked lists,that stores the inputed data in a binary text file.
i have a probelm with to operations on binary file,
my data in the binary file stored like this : name,family name,phonenumber...over and over again.
now,how can i update and delete and entery from the binary file not using a temporary binary file or a linked list ( if possible
any ideas will be mostly appriciated
thank you
May I suggest that you use SQLite instead? Its author has described SQLite has a replacement for fopen(), and in this case it could well serve as that.
Look up a C++ Reference and learn How To Ask Questions The Smart WayOriginally Posted by Bjarne Stroustrup (2000-10-14)
no no,i need a solution within c limits,using c original header files,or smth like that
:\
'binary text file' doesn't make sense, that's an oxymoron.
Which is it, a binary file, OR a text file? Can you yourself read the whole thing using notepad?
Please show the record data structure or serialisation code.
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Advice: Take only as directed - If symptoms persist, please see your debugger
Linus Torvalds: "But it clearly is the only right way. The fact that everybody else does it some other way only means that they are wrong"
>now,how can i update and delete and entery from the binary file not using a temporary binary file or a linked list
It is pretty difficult to do what you want without the temp file. It would make your life more easier if you use the temp file then rename the temp file to orginal filename. Otherwise to will have to work along with all these offset value which makes it messy.
ssharish
Updating is easy, you just fseek() to the record in question, then do an fwrite()
Appending is similarly just as easy.
Deleting a record is easy, so long as you have a flag in the record which indicates 'deleted'. In this case, it's just another kind of update.
To remove a record, you physically have to copy all the records you want to keep to another file. Some applications call this "compact databases", which is something they do at say program exit (or user choice), rather than every time something happens.
If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
If at first you don't succeed, try writing your phone number on the exam paper.
---------Code:void update_file() { FILE *fp; int cmp_name,cmp_family; list_char number,familyname,name,sname,sfamilyname; fp=fopen("binar.bin","ab+rb"); printf("Please Enter the name and the family name that you want to update:\n\n"); printf("please enter name\n"); scanf("%s",&sname); printf("please enter familyname\n"); scanf("%s",&sfamilyname); while(!feof(fp)&&(cmp_name=strcmp(sname,name)!=0)) { fread(name,sizeof(list_char),1,fp); fread(familyname,sizeof(list_char),1,fp); fread(number,sizeof(list_char),1,fp); } if(cmp_family=strcmp(familyname,sfamilyname)==0) printf("please enter new name\n"); scanf("%s",&sname); printf("please enter new familyname\n"); scanf("%s",&sfamilyname); fseek(fp,-3*sizeof(list_char),SEEK_CUR); fwrite(&sname,sizeof(list_char),1,fp); fwrite(&sfamilyname,sizeof(list_char),1,fp); fwrite(&number,sizeof(list_char),1,fp); fclose(fp); }
thats what i did some days ago,but its not working so much,any ideas?
Learn to properly indent your code. You won't be able to spot errors if you write it that way.
