read/write files


 
Thread Tools Search this Thread
Top Forums Programming read/write files
# 1  
Old 11-11-2009
read/write files

Hi all,

I have a problem with some read/write functions.
I have a .bin file which contains a lot of structures as follows:

Code:
struct alumno
{
char id[10]; 
char apellido1[32];
char apellido2[32];
char nombre[32];
float nota1p; 
float nota2p; 
float notamedia; 
char photofilename[20]; 

};

What I have to do is read the file, firstly one structure by one, and then all the file at once and change the value if notamedia is less than 3. I'm using read() and lseek(), but I'm very loss Smilie. Somebody can give me a hand in developing the code. I believe is not too big.
Thanks in advance for the help

Last edited by pludi; 11-12-2009 at 04:43 AM.. Reason: code tags, please...
# 2  
Old 12-04-2009
you still have this problem? maybe i could help you.
# 3  
Old 12-05-2009
hello ..
you can read the structures one by one. using the simple read command.
given by your information-> the size of your structure would be.
(assuming 32 bit architecture) . you can add the sizes of the tokens or you can do a simple sizeof() to find the value.
then read the values in a buffer one by one and extract the values one by one.
Reply..if you need more.
Regards Smilie
# 4  
Old 12-06-2009
Quote:
Somebody can give me a hand in developing the code.
Sure, show us your sample code. We could move further from there.
Login or Register to Ask a Question

Previous Thread | Next Thread

9 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Read and write operations on files.

Dears. kindly guide !!! I have data, which is delimited by | . it should contain 26 columns, but one column data contain | makes few row to 27 columns. I want to find rows have 27 columns and then concatenate the specific columns to single column to make it 26 columns. Kindly help, Can... (3 Replies)
Discussion started by: sadique.manzar
3 Replies

2. Shell Programming and Scripting

Read input files and merge them in given order and write them to input one param or one file

Dear Friends, I am looking for a shell script to merge input files into one file .. here is my idea: 1st paramter would be outfile file (all input files content) read all input files and merge them to input param 1 ex: if I pass 6 file names to the script then 1st file name as output file... (4 Replies)
Discussion started by: hyd1234
4 Replies

3. Shell Programming and Scripting

How to read and write last modified timestamp to files?

Need help reading file last modified date in format: Filename (relative path);YYYYMMDDHHMMSS And then write it back. My idea is to backup it to a text file to restore later. Checked this command but does not work: Getting the Last Modification Timestamp of a File with Stat $ stat -f... (5 Replies)
Discussion started by: Tribe
5 Replies

4. IP Networking

read/write,write/write lock with smbclient fails

Hi, We have smb client running on two of the linux boxes and smb server on another linux system. During a backup operation which uses smb, read of a file was allowed while write to the same file was going on.Also simultaneous writes to the same file were allowed.Following are the settings in the... (1 Reply)
Discussion started by: swatidas11
1 Replies

5. Shell Programming and Scripting

Find all files with group read OR group write OR user write permission

I need to find all the files that have group Read or Write permission or files that have user write permission. This is what I have so far: find . -exec ls -l {} \; | awk '/-...rw..w./ {print $1 " " $3 " " $4 " " $9}' It shows me all files where group read = true, group write = true... (5 Replies)
Discussion started by: shunter63
5 Replies

6. Shell Programming and Scripting

SED command for read and write to different files

Hi I need some help on SED command I am writing a shell script which does the following: 1. Read one line at a time from a file abc.txt which has millions of lines 2. Prefix each line read with some text " 3. Post fix each line read with a quote " 4. Write the new modified... (11 Replies)
Discussion started by: gaurav_1711
11 Replies

7. UNIX for Dummies Questions & Answers

how to read or write device files

hi everybody, i am working in device drivers.As a beginner to this field ,i dont know how to read or write device files. Will copy_to_user and copy_from_user help me? I have created a device file using mknod command .Can anybody help me in this regard :confused thanks in advance sriram (1 Reply)
Discussion started by: sriram.ec
1 Replies

8. Shell Programming and Scripting

Script with read/write Files

Hello, I am a Newbie in ksh Unix Script. So I must write a ksh/sh script who read character at a position in a File. So also it must read all the lines who belongs at these characters , then write these lines in a another File. Can you help me , or give little councils to advance with my... (5 Replies)
Discussion started by: steiner
5 Replies

9. UNIX for Dummies Questions & Answers

How to read and write files one line at a time.

Hi! All! I am wirting a shell script in which i want to read one line at a time from the file and write it simultaneouly to other file one line at a time. Please let me know about some shell utility which can help me out. Thanx. If further clarifications are needed then please let me know... (2 Replies)
Discussion started by: s_chopra
2 Replies
Login or Register to Ask a Question