vector< vector< string> > theList;
vector<string>::iterator it;
 
vector<string>& innerList = theList[0];
it = innerList.begin();
for( ; it != innerList.end(); it++)
{
  // blabla
}

#include <iostream>
#include <iomanip>
#include <vector>
 
int main()
{
  std::vector< std::vector<int> > v;
 
  for ( int i = 0; i < 10; i++ ) {
    v.push_back ( std::vector<int>() );
 
    for ( int j = 0; j < 10; j++ )
      v[i].push_back ( i + j );
  }
 
  std::vector< std::vector<int> >::iterator row_it = v.begin();
  std::vector< std::vector<int> >::iterator row_end = v.end();
 
  for ( ; row_it != row_end; ++row_it ) {
    std::vector<int>::iterator col_it = row_it->begin();
    std::vector<int>::iterator col_end = row_it->end();
 
    for ( ; col_it != col_end; ++col_it )
      std::cout<< std::setw ( 3 ) << *col_it;
    std::cout<<'\n';
  }
}