DaniWeb Forum Index > Software Development > C++

counting a string array

Please support our C++ advertiser: Intel Parallel Studio Home

•

Join Date: Nov 2008

Posts: 1

Reputation: empathy is an unknown quantity at this point

Solved Threads: 0

empathy

Offline

Newbie Poster

counting a string array

Nov 3rd, 2008

hi

i am trying to count the occurrences of different words in a string array.

while(end of array)
{
while(end of array)
{
compare ith element with all other elements
inc counter
}
increment the element number
}

but i guess something is terribly wrong here as i am not able to get the required result. can someone point me out where i could have gone wrong!!! thanks!!!!

•

Join Date: Oct 2008

Posts: 29

Reputation: jbrock31 is an unknown quantity at this point

Solved Threads: 1

jbrock31

Offline

Light Poster

Re: counting a string array

Nov 3rd, 2008

I would recommend posting your code. You are not going to find anyone here that will give you answers without showing your effort.

•

Join Date: Jan 2008

Posts: 119

Reputation: kux is on a distinguished road

Solved Threads: 10

kux

Offline

Junior Poster

Re: counting a string array

Nov 3rd, 2008

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
	char *stringarray[] = { "mama", "tata", "bunica", "mama", "tata", "georgel" };
	map< char*, int > mycountingmap; 
 
	for ( size_t i = 0; i < sizeof( stringarray ) / sizeof( char* ); ++i )
		++mycountingmap[ stringarray[i] ] ;
 
       //print result
       for ( size_t i = 0; i <  sizeof( stringarray ) / sizeof( char* ); ++i )
		cout<<stringarray[i] <<" "<< mycountingmap[ stringarray[i] ] <<" times"<<endl;
	char *stringarray[] = { "mama", "tata", "bunica", "mama", "tata", "georgel" };
	map< char*, int > mycountingmap; 
	
	for ( size_t i = 0; i < sizeof( stringarray ) / sizeof( char* ); ++i )
		++mycountingmap[ stringarray[i] ] ;

       //print result
       for ( size_t i = 0; i <  sizeof( stringarray ) / sizeof( char* ); ++i )
		cout<<stringarray[i] <<" "<< mycountingmap[ stringarray[i] ] <<" times"<<endl;

•

Join Date: Jul 2008

Posts: 2,001

Reputation: ArkM has much to be proud of

Solved Threads: 343

ArkM

Offline

Postaholic

Re: counting a string array

Nov 3rd, 2008

At first you must load map contents (where is the code? ). But you have another problem: std::map<char*,int> can't help you because its key_type is char* but operator< for char* type compares pointer values, not referred C-strings. Therefore you will get wrong dictionary...

It's possible to define a simple wrapper class for char* type with its own operator< but it seems you can't do it now. So consider map<string,int> type for your dictionary: it's less effective but a very simple solution.

Now get F1 help on map insertion (or google it) then send us the next version of the program product...

Last edited by ArkM; Nov 3rd, 2008 at 3:47 pm.

•

Join Date: Jan 2008

Posts: 119

Reputation: kux is on a distinguished road

Solved Threads: 10

kux

Offline

Junior Poster

Re: counting a string array

Nov 4th, 2008

•

Originally Posted by ArkM

At first you must load map contents (where is the code? ). But you have another problem: std::map<char*,int> can't help you because its key_type is char* but operator< for char* type compares pointer values, not referred C-strings. Therefore you will get wrong dictionary...

It's possible to define a simple wrapper class for char* type with its own operator< but it seems you can't do it now. So consider map<string,int> type for your dictionary: it's less effective but a very simple solution.

Now get F1 help on map insertion (or google it) then send us the next version of the program product...

map<char*,int> is ok for he's requirements. He just has to count them, not have them in a sorted dictionary

•

Join Date: Jul 2008

Posts: 2,001

Reputation: ArkM has much to be proud of

Solved Threads: 343

ArkM

Offline

Postaholic

Re: counting a string array

Nov 4th, 2008

To kux

•

map<char*,int> is ok for he's requirements. He just has to count them, not have them in a sorted dictionary

Alas, all four text literals "mama" (for example) have different addresses (as usually). So map<char*,int> contains four different elements for the word "mama"! Obviously, it's not ok for his/her requirements. Read the original post carefully:

•

i am trying to count the occurrences of different words in a string array.

•

Join Date: Jan 2008

Posts: 119

Reputation: kux is on a distinguished road

Solved Threads: 10

kux

Offline

Junior Poster

Re: counting a string array

Nov 4th, 2008

•

Originally Posted by ArkM

To kux

Alas, all four text literals "mama" (for example) have different addresses (as usually). So map<char*,int> contains four different elements for the word "mama"! Obviously, it's not ok for his/her requirements. Read the original post carefully:

hmm, i think you are wrong here. I mean i'm shure you are wrong here. On my STL implementation std::map has a template specialization that for char* keys uses the char* content to identify keys, not the address. Just try it. It will corectly count the words...