Solved

Format data from a file

Posted on 2004-05-02
8
270 Views
Last Modified: 2010-04-01
In my code, I read data from a file..here are the first 2 lines...

990102
030901

I stored each line and what I want to do is put it in this format:
01/02/99
09/01/03

Basically, what I want to do is scan through the buffer (where I stored the line), and put them in that format.

How would I do this?
0
Comment
Question by:jewee
  • 4
  • 4
8 Comments
 
LVL 4

Expert Comment

by:skypalae
ID: 10974790
Hi jewee,

char dd[3], mm[3], yy[3] ;

scanf ("%2s%2s%2s", yy, dd, mm) ;
printf ("%s/%s/%s", dd, mm, yy) ;

or sscanf() and sprintf() if you want to manipulate strings instead of input output.

S.
0
 

Author Comment

by:jewee
ID: 10974838
When I read in data to a file, that data is at the end, so I read it into a char buffer array.  Should I just set, for example, the first 2 bytes which is 99 into yy...etc??
0
 

Author Comment

by:jewee
ID: 10974845
or use a pointer and scan through the buffer?

sample code?
0
Announcing the Most Valuable Experts of 2016

MVEs are more concerned with the satisfaction of those they help than with the considerable points they can earn. They are the types of people you feel privileged to call colleagues. Join us in honoring this amazing group of Experts.

 
LVL 4

Expert Comment

by:skypalae
ID: 10974950
I don't understad what you really want to do now. Do you have a file containing lines "990102", "010901" etc., or you have some data and inside are these dates? Well, let's pass this and suppose that you have allready read a line that contains your date.

If you have a string containing "990102" in the middle it still depends whether the position is fixed or it is prefixed with a word (possibly "date:") or the position of the date is fixed (like 3rd word from beginning).

but if you know the exact position of the date in the string (lets say 'a') you can:
separate the date copying the substring out: strncpy (szDate, &szLine[a], 6) ;
and sscanf() it
or you can separate it using numbers
    int dd, mm, yy ;
    scanf ("%2d%2d%2d, &yy, &dd, &mm)

or you can get the numbers by your own:
    yy = (szLine[a]-'0')*10 + (szLine[a+1]-'0') ;
    dd = (szLine[a+2]-'0')*10 + (szLine[a+3]-'0') ;
    mm = (szLine[a+4]-'0')*10 + (szLine[a+5]-'0') ;

there are numerous approaches, you have to decide what to do according to your specific situation (for example if you want to calculate with the date further it would be better to get numbers instead of substrings).

S.
0
 

Author Comment

by:jewee
ID: 10974986
I know exactly where the string is within the line...this is how I extract it...

std::string last_field = line.substr(42);
0
 

Author Comment

by:jewee
ID: 10974995
I'm confused with how I use sscanf to separate it considering the location of the year, month and day needs to be changed to month, year, and day.
0
 
LVL 4

Accepted Solution

by:
skypalae earned 500 total points
ID: 10975013
so you answered you question perfectly by ourself :)

std:: string yy = last_field.substr(0, 2) ;
std:: string dd = last_field.substr(2, 2) ;
std:: string mm = last_field.substr(4, 2) ;

cout << dd << "/" << mm << '/' << yy ;

S.
0
 
LVL 4

Expert Comment

by:skypalae
ID: 10975019
And don't get confused by scanf and printf. These are C (not C++) functions and if you don't understand them don't bother. You can learn C later.
0

Featured Post

Free Tool: IP Lookup

Get more info about an IP address or domain name, such as organization, abuse contacts and geolocation.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

IntroductionThis article is the second in a three part article series on the Visual Studio 2008 Debugger.  It provides tips in setting and using breakpoints. If not familiar with this debugger, you can find a basic introduction in the EE article loc…
Basic understanding on "OO- Object Orientation" is needed for designing a logical solution to solve a problem. Basic OOAD is a prerequisite for a coder to ensure that they follow the basic design of OO. This would help developers to understand the b…
The goal of the video will be to teach the user the concept of local variables and scope. An example of a locally defined variable will be given as well as an explanation of what scope is in C++. The local variable and concept of scope will be relat…
The viewer will learn how to clear a vector as well as how to detect empty vectors in C++.

830 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question