Example Program
Iterator Basics
Simple iterator functions.
File "iterator.cpp"
1#include <iostream>
2#include <seqan/sequence.h>
3#include <seqan/file.h>
4
5int main()
6{
7    seqan::String<char> str = "admn";
The metafunction Iterator returns the iterator type for a given container type.
8    seqan::Iterator<seqan::String<char> >::Type it = begin(str);
9
10    std::cout << *it;                //output: 'a'
The following lines show a loop through str in the standard library style:
11    while (it != end(str))           //output: "admn"
12    {
13        std::cout << *it;
14        ++it;
15    }
16    std::cout << std::endl;
Seqan offers an alternative style for accessing iterators that avoids operators. Note that the functions goBegin and atEnd do net get str as arguments, because it2 is a rooted iterator. The following loop increments each character in str:
17    seqan::Iterator<seqan::String<char>, seqan::Rooted >::Type it2 = begin(str);
18    for (goBegin(it2); !atEnd(it2); goNext(it2)) 
19    {
20        ++value(it2);
21    }
This is a reverse loop through str. Note that goPrevious is called before the value of it2 is accessed, because the end position of a container is the position behind the last item in the container:
22    goEnd(it2);
23
24    while (!atBegin(it2))              //output: "oneb"
25    {
26        goPrevious(it2);
27        std::cout << getValue(it2);
28    }
29    std::cout << std::endl;
Another (write only) way to access the value of an iterator is assignValue:
30    assignValue(begin(str), 'X');
31
32    std::cout << str << std::endl;        //output: "Xeno"
33    
34
35    return 0;
36}
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