Strange too few template-parameter-lists error

Strange too few template-parameter-lists error

set<unsigned int> setId;
vector<int> vecNode;
for (size_t i = 0,set<unsigned int>::iterator it = setId.begin(); i <
vecNode.size() && it != setId.end(); i++,it++ ){}
the compiler report: error: too few template-parameter-lists
but if I write like this:
set<unsigned int> setId;
vector<int> vecNode;
size_t i = 0;
for (set<unsigned int>::iterator it = setId.begin(); i < vecNode.size() &&
it != setId.end(); i++,it++ ){}
the compilation succeeds.
so why?