deque or vector clear...

There are vector< vector < int > > test;

test have some datas.

i want to clear vector< vector < int > > test.

which is correct?

1. vector< vector < int > >::iterator iter1 = test.begin();
while(iter1 != test.end())
{
(*iter1).clear();
iter1++;
}
test.clear();

2. just..call test.clear().