Is it conflict between scanf and fgets

[alokdotnet]

dear friends,
past 5 hours i working out this problem, here a confliction between scanf and fgets...
may be i m using wrong term conflict, but i m going to explain you the exact problem..

just look at the code segment, i will explain in code itself with the help of comments
please consider the declaration of all variable...

for reference
here is the structure
 typedef struct
      6         {
      7
      8             char name[10];
      9             char phone[10];
     10             char address[20];
     11             char amount[10] ;
     12             int inactive ;
     13
     14         } RECORD ;

 
printf("Account Detail change form\n");
     23         printf("Type your account no :") ; // promt
     24         scanf("%d", &accno) ; // here taking input from user into accno
     25         fd = open("dbase.dat",O_RDWR); // opening database file ( can be omit)
     26         lseek(fd,(accno -1)*sizeof(RECORD),SEEK_SET) ; // seeking the record ( can be omit)
     27         //set lock
     28         lockf(fd,sizeof(RECORD),F_LOCK) ; // setting lock ( can be omit)
     29         //end
     30         rec = (RECORD *)malloc(sizeof(RECORD)) ; // mallocing the memory to RECORD
     31         read(fd,rec,sizeof(RECORD)) ; // reading info from record ( can be omit)
     32         printf("Info in dbase as follows :\n") ; 
     33         printf("Address : %s",rec->address) ; 
     34         printf("Phone : %s", rec->phone) ;
     35         printf("**********NOW enter the new info*************\n") ;
     36         printf("Address :");// here all the problem starts
     37         fgets(rec->address,20,stdin) ;// when i run the program my prog skip this and not take 
                              // any input into rec->address, and jump to next promt...
     38        
     39         printf("Phone Number :") ; //printf this 
     40         fgets(rec->phone,10,stdin) ; // and jump here and ask for input
                                             // and leave rec->address array empty
     41         printf("******** Thank you *******\n") ;
     42         write(fd,rec,sizeof(RECORD)) ;

I have guess that when i giving input to var accno, and pressing enter to tell prog that i hav enter the input, the enter is still in the keyboard buffer, stdin , and first fgets is taking it and going to second fgets.
tell if my gusss is right, tell how can i resolve it, if not tell what you think and how can i resolve it.
if still problem is not clear you can ask for more clearification.
thankx

[quzah]

Don't mix input methods. Stick to one or the other. Consider using fgets with sscanf.


Quzah.

[OnionKnight]

Yes scanf will leave the newline in the buffer. The FAQ has some solutions. I prefer this;

int c;
while ((c = getchar()) != '\n' && c != EOF);

[alokdotnet]

Don't mix input methods. Stick to one or the other. Consider using fgets with sscanf.


Quzah.

Dear Quzah, sscanf has following protype

int sscanf(const char *str, const char *format, ...);

if i m using it then i have to pass char * as first argument, but here i want to take input as integer, then how i will do it.
plz clearify it.

[OnionKnight]

if i m using it then i have to pass char * as first argument, but here i want to take input as integer, then how i will do it.
plz clearify it.

Use atoi() on the string or similar.

[whiteflags]

You already know how to use scanf, what Quzah suggested is similar. Get a string from the user first: sscanf checks a string for a format instead of what the user directly inputs.

[alokdotnet]

Use atoi() on the string or similar.

But friend problem is here, to convert integer to string, and atoi changes ascii to integer...
another function is there itoa(), but his is not standard ANSI function, and not supported by GCC.
i can use sprintf for that same purpose, but here it not as requirnment, if you have seen the code, just below i have several operation where i m useing accno for comparisions.

[Dave_Sinkula]

Same thing, over and over:
User Input: Strings and Numbers [C]

[OnionKnight]

But friend problem is here, to convert integer to string, and atoi changes ascii to integer...
another function is there itoa(), but his is not standard ANSI function, and not supported by GCC.
i can use sprintf for that same purpose, but here it not as requirnment, if you have seen the code, just below i have several operation where i m useing accno for comparisions.

I am not sure what you're asking, and I see no comparisons done with accno.
The problems I can see with the code is the scanf/fgets intervention and that you're overwriting the account after the current one in your database file.

[alokdotnet]

char strnum[20] ;
int accno;
......
fgets(strnum,sizeof strnum,stdin);
sscanf(strnum,"%d",&accno) ;
......

by this my problem is solved....
good way to come out such problems..

[Salem]

> rec = (RECORD *)malloc(sizeof(RECORD)) ;
See the FAQ on casting malloc as well.

Also, can you stop line-numbering your code, it makes it too hard to copy/paste to an editor.
If you want to highlight specific lines, then use a /* this line */ comment, and refer to that in your text.