Ad:

C++ Discussion Thread
Unsolved
Views: 5468

Page 1
2
Next

You are currently viewing page 1 of this multi-page discussion thread

Sep 19th, 2006

Finding the union of two strings

Expand Post »

I am programming in C++ and am attempting to find the intersection of two strings, only the items common to both and thus return a third string with these items. Essentially, I am trying to write
the code for the STL library set_intersection.
To approach this problem I thought of I can use two nested loops one loop to cycle thru each string. Then having a variable to compare values in common, which means I would
have to have a temp variable to store common elements.
something similar to this:

C++ Syntax (Toggle Plain Text)
string names[] = {"AMC", "ANZ", "AMX"};            
 for( int i = 0; i < 3; i++ ) {
   for( int j = 0; j < 3; j++ ) {
     cout << names[i].compare(names[j] ) << " ";
   }
   cout << endl;
 }
string names[] = {"AMC", "ANZ", "AMX"};            
 for( int i = 0; i < 3; i++ ) {
   for( int j = 0; j < 3; j++ ) {
     cout << names[i].compare(names[j] ) << " ";
   }
   cout << endl;
 }

Any further sugestions would be great,
Thanks,
I

Similar Threads

fopen: No such file or directory in Linux Applications and Software

hay_man

Reputation Points: 38

Solved Threads: 0

Newbie Poster

Offline

16 posts
since Jun 2006

Permalink

Sep 19th, 2006

Re: Finding the union of two strings

the compare() function is not what you need. It only tells you whether one string is the same as the other. you need to check the two strings one character at a time and create a third string that contains the characters which are in both strings. For example, the first two strings have the letters 'A' and 'M' in both strings, so a third string will contain "AM".

Ancient Dragon

Sponsor

Team Colleague

Featured Poster

Reputation Points: 5608

Solved Threads: 2283

Retired and Enjoying Life

Online

21,963 posts
since Aug 2005

Permalink

Sep 19th, 2006

Re: Finding the union of two strings

How does one check each char at a time? As you can see, i've only had success at comparing a whole string. Thanks

hay_man

Reputation Points: 38

Solved Threads: 0

Newbie Poster

Offline

16 posts
since Jun 2006

Permalink

Sep 19th, 2006

Re: Finding the union of two strings

you can use a loop. Something like below. The find() method will search one string for an instance of another string and return the position where its at.

C++ Syntax (Toggle Plain Text)
string str1 = "ABC";
string str2 = "BCD";
string result;
 
for(int i = 0; i < str2.length(); ++)
{
   if( str1.find( str2[i] ) != string::npos )
       result += str2[i];
}
string str1 = "ABC";
string str2 = "BCD";
string result;

for(int i = 0; i < str2.length(); ++)
{
   if( str1.find( str2[i] ) != string::npos )
       result += str2[i];
}

Ancient Dragon

Sponsor

Team Colleague

Featured Poster

Reputation Points: 5608

Solved Threads: 2283

Retired and Enjoying Life

Online

21,963 posts
since Aug 2005

Permalink

Sep 19th, 2006

Re: Finding the union of two strings

Fantastic, gr8 help Ancient Dragon. After 8hrs of sitting behind this screen your saviour was lifeline!

hay_man

Reputation Points: 38

Solved Threads: 0

Newbie Poster

Offline

16 posts
since Jun 2006

Permalink

Sep 21st, 2006

Re: Finding the union of two strings

You should also look at this

Last edited by Micko; Sep 21st, 2006 at 2:17 am.

Micko

Reputation Points: 55

Solved Threads: 6

Junior Poster

Offline

148 posts
since Aug 2005

Permalink

Sep 21st, 2006

Re: Finding the union of two strings

nicko, thats my post. thanks anywayy

hay_man

Reputation Points: 38

Solved Threads: 0

Newbie Poster

Offline

16 posts
since Jun 2006

Permalink

Sep 21st, 2006

Re: Finding the union of two strings

Click to Expand / Collapse Quote originally posted by hay_man ...

nicko, thats my post. thanks anywayy

Your solution was nearly identicale to mine except your made a check to insure duplicates are not inserted into the new string. If you already knew the solution why did you post the question in this thread?:eek:

:rolleyes:

Ancient Dragon

Sponsor

Team Colleague

Featured Poster

Reputation Points: 5608

Solved Threads: 2283

Retired and Enjoying Life

Online

21,963 posts
since Aug 2005

Permalink

Sep 21st, 2006

Re: Finding the union of two strings

because that is dealing wih strings i want to adapt it to handle vectors

hay_man

Reputation Points: 38

Solved Threads: 0

Newbie Poster

Offline

16 posts
since Jun 2006

Permalink

Sep 21st, 2006

Re: Finding the union of two strings

now you are asking a completly different question. vectors of what? strings? do you want to create a vector that is a union of two other vectors, where each string in the new vector is the union of the corresponding strings in two or more other vectors? The algorithm would be almost identical to what has already been posted.

Ancient Dragon

Sponsor

Team Colleague

Featured Poster

Reputation Points: 5608

Solved Threads: 2283

Retired and Enjoying Life

Online

21,963 posts
since Aug 2005

Page 1
2
Next

This thread is more than three months old

No one has posted to this discussion for at least three months. Please let old threads die and do not reply to them unless you feel you have something new and valuable to contribute that absolutely must be added to make the discussion complete. Otherwise, please start a new thread in this forum instead.

Previous Thread in C++ Forum Timeline: Buffering

Next Thread in C++ Forum Timeline: adding a '\' to a CString object

DaniWeb Message

Cancel Changes

User Name
Password