Thread: sorting ABC order

currently I have this method of sorting with c++ (ABC order)

Code:

#include <algorithm>
#include <string>
#include <ctype.h>
struct sort_pred {

    bool operator()(const string &left,const string &right) {

        for(string::const_iterator lit=left.begin(), rit=right.begin(); lit != left.end() && rit != right.end(); ++lit,++rit)

        if( tolower(*lit) <  tolower(*rit))

             return true;

        else if( tolower( *lit ) > tolower( *rit ) )

             return false;

        if( left.length() < right.length() )

            return true;

        return false;

    }

};

int main()
{
//some vector<string> vec
sort(vec.begin(),vec.end(),sort_pred());
}

Is there a more simple way to sort words in abc order?
I have heard that in Java there is simply the "compareTo" method that returns positive if first word is closer to A than the second.. (along with a compareTo for doubles and other types as well)

is there a similar method in c++ stl?

hmm what if I was sorting a vector of structs which contain a string?

i would still need the predicate function right?

(thats what it really is, but i didnt want to include the struct since it would overcomplicate my question)

Code:

struct player
{
string name;
int id;
}

int main()
{
vector<player> players;
sort(players.begin(), players.end());
//INCORRECT
}

THANKS!!!

The fact that you're using tolower at all suggests to me that you're looking for a case-insensitive sort of those strings. If this is the case all you do is:

Code:

#include <cctype> // for toupper
#include <string>
#include <algorithm>
using namespace std;

bool operator()(string left, string right) {
    transform(left.begin(), left.end(), left.begin(), (int(*)(int)) toupper);
    transform(right.begin(), right.end(), right.begin(), (int(*)(int)) toupper);
    return left < right;
}

Now if this is a struct then you wont want to modify the contents of those strings when comparing them, so be sure you make a copy first in that case.