Solved

100pt question malloc()

Posted on 2000-04-30
5
175 Views
Last Modified: 2010-04-02
Here is the question for 100 pts! help :)
 
http://www.experts-exchange.com/jsp/qShow.jsp?ta=cprog&qid=10336579 
0
Comment
Question by:cisk
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
5 Comments
 
LVL 5

Accepted Solution

by:
pitonyak earned 50 total points
ID: 2764929

I looked at your code and you are freeing the code malloced code, but
I suspect that this is not what you intended to do.
The problem is that all that you are doing is simply freeing memory.
For example, your code there are the following three lines:

   printf("Before free %s --- ", tbp->entry[j].name);
   free(tbp->entry[j].name);
   printf("After free %s\n", tbp->entry[j].name);

The first line is OK assuming that you do not have a null pointer.
The second line is ok because the memory was malloced.
The third line is WRONG because you printed memory that you just deleted.
What you really want to do is to swap the names.
I assume that nothing else points to the memory so you could do this as follows:


for(i=0; i < n; i++) {
   for(j=0; j< n-1; j++) {
      if(strcmp(tbp->entry[j].name, tbp->entry[j+1].name) > 0) {
         // switch names
         char* temp = tbp->entry[j].name;
         tbp->entry[j].name = tbp->entry[j+1].name;
         tbp->entry[j+1].name = temp;
         // switch the phone numbers
         temp = tbp->entry[j].telNum;
         tbp->entry[j].name = tbp->entry[j+1].telNum;
         tbp->entry[j+1].telNum = temp;
      }
   }
}

0
 

Expert Comment

by:843988
ID: 2928069
I agree your answer, pitonyak
0
 
LVL 1

Author Comment

by:cisk
ID: 2929257
Adjusted points from 0 to 50
0
 
LVL 1

Author Comment

by:cisk
ID: 2929260
Comment accepted as answer
0
 
LVL 1

Author Comment

by:cisk
ID: 2929261
I'm sorry but i canceled this question a long time ago and i guess i thought it was going to delete this one too.. i figured out why a few minutes after i pointed..

 BUT i'm going to ago ahead and ive 50 points to pitonyak because he was right and he answered in 2 hours
=)
cool?
Cisk
0

Featured Post

Enroll in July's Course of the Month

July's Course of the Month is now available! Enroll to learn HTML5 and prepare for certification. It's free for Premium Members, Team Accounts, and Qualified Experts.

Question has a verified solution.

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

Written by John Humphreys C++ Threading and the POSIX Library This article will cover the basic information that you need to know in order to make use of the POSIX threading library available for C and C++ on UNIX and most Linux systems.   [s…
  Included as part of the C++ Standard Template Library (STL) is a collection of generic containers. Each of these containers serves a different purpose and has different pros and cons. It is often difficult to decide which container to use and …
The viewer will learn how to use the return statement in functions in C++. The video will also teach the user how to pass data to a function and have the function return data back for further processing.
The viewer will learn how to clear a vector as well as how to detect empty vectors in C++.

626 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