Thread: string iterator

  1. #1
    Registered User Micko's Avatar
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    string iterator

    I'm reading one tutorial about STL iterators. I've noticed that there is iterator support for strings. For example I can do something lke this:
    Code:
    #include <iostream>
    #include <string>
    
    using namespace std;
    
    int main()
    {
        string s("Kivla");
        string::iterator it;
       
       for (it = s.begin(); it != s.end();++it)
       {
           cout<<*it;
       }
    }
    I wonder what is the benefit of using iterators with strings (there must be some benefit otherwise iterators wouldn't have been defined)?
    In which cases they are useful for strings?

    - Micko
    Gotta love the "please fix this for me, but I'm not going to tell you which functions we're allowed to use" posts.
    It's like teaching people to walk by first breaking their legs - muppet teachers! - Salem

  2. #2
    Registered User hk_mp5kpdw's Avatar
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    They are usefull in all the situations where you want to use the string object with the STL.

    Code:
    #include <iostream>
    #include <algorithm>
    #include <string>
    #include <cctype>
    
    using namespace std;
    
    int main()
    {
        string s("Kivla");
    
        cout << "Before toupper: " << s << endl;
        transform(s.begin(),s.end(),s.begin(),toupper);
        cout << "After toupper : " << s << endl;
        sort(s.begin(),s.end());
        cout << "After sort    : " << s << endl;
    
        return 0;
    }
    Output:
    Code:
    Before toupper: Kivla
    After toupper : KIVLA
    After sort    : AIKLV
    "Owners of dogs will have noticed that, if you provide them with food and water and shelter and affection, they will think you are god. Whereas owners of cats are compelled to realize that, if you provide them with food and water and shelter and affection, they draw the conclusion that they are gods."
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  3. #3
    Code Goddess Prelude's Avatar
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    This is a contrived multi-example, but it's not a big step to a potential real world use:
    Code:
    #include <deque>
    #include <iostream>
    #include <string>
    
    using namespace std;
    
    int main()
    {
      string s ( "is a test" );
      string t ( "This " );
      deque<char> string_buffer ( s.begin(), s.end() );
    
      for ( string::reverse_iterator it = t.rbegin(); it != t.rend(); ++it )
        string_buffer.push_front ( *it );
    
      s = string ( string_buffer.begin(), string_buffer.end() );
      cout<< s <<endl;
    }
    My best code is written with the delete key.

  4. #4
    Registered User Micko's Avatar
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    Hmm, interesting, I'll dive more into STL... I almost sure I'll have questions regarding STL very soon. I hope I can count on your help.
    Thanks hk_mp5kpdw and thanks Prelude
    Gotta love the "please fix this for me, but I'm not going to tell you which functions we're allowed to use" posts.
    It's like teaching people to walk by first breaking their legs - muppet teachers! - Salem

  5. #5
    Tropical Coder Darryl's Avatar
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    well if you think of strings as just another container then:
    1: You have consistency with the other container
    2: Many(most) of the std::algorithm functions use iterators as others have shown by example

  6. #6
    Registered User Micko's Avatar
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    Well, I'm pretty new to STL, I was playing with string class and container vector from time to time, but never actually scratch under the surface. Of coures that is going to change very soon...
    Gotta love the "please fix this for me, but I'm not going to tell you which functions we're allowed to use" posts.
    It's like teaching people to walk by first breaking their legs - muppet teachers! - Salem

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