# Page Index Count Children

Example for using a countChildren and countOccurrences for indices.

This example shows how to iterate over a suffix tree and print the number of children and the number of occurrences of the node representatitves.

    ///An example to demonstrate  the functions countChildren and countOccurrences
    #include <iostream>
    #include <seqan/index.h>

    using namespace seqan;

    int main()
    {
        //We begin with a String to store our sequence.
        String<char> myString = "How many wood would a woodchuck chuck. A woodchuck chucks as much wood as a woodchuck could";

        //Then we create an Index of this StringSet.
        typedef Index<String<char> > TMyIndex;
        TMyIndex myIndex(myString);

        // We will use a TopDown Iterator that supports parent links, ommits
        // empty edges and traverses the index in preorder to print out the number of
        // children at each node (not the number of leafs in the subtree).
        Iterator<TMyIndex, TopDown<ParentLinks<PreorderEmptyEdges> > >::Type tdIterator(myIndex);
        Size<TMyIndex>::Type count;

        while (!atEnd(tdIterator))
        {
            //We print out the representatives of all nodes that have more than 3
            //children and the number of occurrences. Also, we print a message if a node
            //is a leaf.
            count = countChildren(tdIterator);
            if (count >= 3)
            {
                std::cout << "Representative " << representative(tdIterator) << " has " <<  count << " children and ";
                std::cout << countOccurrences(tdIterator) << " occurrences " << std::endl;
            }
            if (isLeaf(tdIterator))
                std::cout << "The node is a leaf " << std::endl;

            tdIterator++;
        }

        return 0;
    }

Demo: demos/dox/index/counting.cpp

The only maximal matches that occur in all 3 sequences are "SeqAn" and "sequence". They occur exactly once and thus are maximal unique matches.

#### Dox Sources

    @page DemoIndexCountChildren Index Count Children

    @brief Example for using a countChildren and countOccurrences for indices.

    This example shows how to iterate over a suffix tree and print the number of
    children and the number of occurrences of the node representatitves.

    @include demos/dox/index/counting.cpp

    The only maximal matches that occur in all 3 sequences are "SeqAn" and
    "sequence". They occur exactly once and thus are maximal unique matches.