Vector of a struct containing another vector

This is a discussion on Vector of a struct containing another vector within the C++ Programming forums, part of the General Programming Boards category; Okay I am implementing an index of words from an input text file. I have a class that contains a ...

  1. #1
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    Vector of a struct containing another vector

    Okay I am implementing an index of words from an input text file. I have a class that contains a vector declared like this:

    Code:
    vector<indexWord> data;
    and a struct declared like this:

    Code:
    struct indexWord {
            std::string value;
            std::vector<int> locations;
    };
    So, in essence, I am storing the words and page numbers in the indexWord struct and then storing that info in the data vector. I have an output function that should output these values. How do I go about telling the function to output the "value" and vector of locations using just the data vector?

  2. #2
    and the Hat of Guessing tabstop's Avatar
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    What exactly is your question? Are you asking how to loop through every element of a vector? Do you want to have cout << indexWord_object do the right thing? What?

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    Yeah I need to loop through the data vector to output the "value" and vector of locations using the data vector. I don't know how to do this.

  4. #4
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    You could add a print() method to indexWord, then iterate through data calling the print() method of each element.

  5. #5
    and the Hat of Guessing tabstop's Avatar
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    That's why vector has iterators. You start at begin(), and you go until you get to end(), and ... well whatever you need to do, you do.
    Code:
    for (vector<indexWord>::iterator current=data.begin(); current!=data.end(); ++current) {
        // do whatever you need to do to the current object, which is *current
    }

  6. #6
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    Code:
     invalid conversion from `const indexWord* const' to `indexWord*'|
    ||=== Build finished: 1 errors, 0 warnings ===|

  7. #7
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    What's the code on the line referenced by that error message?

  8. #8
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    What tabstop just gave me:

    Code:
    for (vector<indexWord>::iterator current=data.begin(); current!=data.end(); ++current)

  9. #9
    Super Moderator VirtualAce's Avatar
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    Use iterators on both vectors. The first iterator will iterate through indexWord objects and the second iterator will iterate through your int vector in the objects. But this structure is also suited to a map. Key off the map on the string value and the map value will be the vector of integers.

    Code:
    typedef std::vector<int> IntVector;
    typedef IntVector::iterator IntVectorIter;
    typedef IntVector::const_iterator IntVectorConstIter;
    
    typedef std::map<std::string,IntVector> MapObject;
    typedef MapObject::iterator MapObjectIter;
    typedef MapObject::const_iterator MapObjectConstIter;
    
    
    MapObject  AllObjects;
    
    //Iterate through map
    MapObjectIter map_iter(AllObjects.begin());
    MapObjectIter map_end(AllObjects.end());
    
    while (map_iter != map_end)
    {
        IntVectorIter vector_iter(map_iter.second.begin());
        IntVectorIter vector_end(map_iter.second.end());
    
        while (vector_iter != vector_end)
        {
            //Do something with vector_iter
        }
    }
    Last edited by VirtualAce; 12-04-2008 at 10:38 PM.

  10. #10
    and the Hat of Guessing tabstop's Avatar
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    Then you didn't do vector<indexWord> data. What is data?

  11. #11
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    There's nothing wrong with that line of code. What's in the for loop?

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    data is the vector...

  13. #13
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    Quote Originally Posted by R.Stiltskin View Post
    There's nothing wrong with that line of code. What's in the for loop?
    nothing right now. just trying to see if that line of code works and it spit out that error.

  14. #14
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    Must be a problem someplace else. This compiles fine for me:
    Code:
    #include <iostream>
    #include <vector>
    
    
    struct indexWord {
            std::string value;
            std::vector<int> locations;
    
            indexWord(std::string s) : value(s) {}
    };
    
    int main() {
      std::vector<indexWord> data;
      data.push_back(indexWord(std::string("once")));
      data.push_back(indexWord(std::string("upon")));
      for(std::vector<indexWord>::iterator current=data.begin(); current!=data.end(); ++current) {
        std::cout << current->value << " ";
      }
      std::cout << "\n";
    }

  15. #15
    and the Hat of Guessing tabstop's Avatar
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    Are you sure it isn't a list? (I think list iterators are const pointers to const, but I don't remember for sure.) Anyway, what you posted doesn't match. So post everything.

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