Syncronizing directories algorithm

I am using Vb.net I need to sync 2 directories so here is my theory so far. I am a seeking a better solution on this idea so far.


I am a Java/PHP programmer so i will use the brackets its easier to outline code for me and im assumin for most of us as well.

syncDir(dirA, dirB){
loop through dirA{
if directory{
syncDir(newDir, dirB & newDir) //u get the idea here
}
else
if dirA.filedatetime < dirB.filedatetime{
copy dirA.file to dirB
}
}
}

now i was thinkin of calling this function as such

syncdir(dirA, dirB);
syncdir(dirB, dirA);

is there a better idea to get this done. I dont like the idea of going through both dirs twice. It doesnt seem efficent to me. If anyone can help thanks alot.