1. Use member insert function instead of copy algorithm and inserter.
2. Minimize capacity: string (s).swap (s)
Clear and minimize capacity : string ().swap (s)
3. Associative containers use equivalence (strict weak ordering) and not equality.
Equivalence: !(w1 < w2) && !(w2 > w1)
In strict weak ordering, equal values are not equivalent!
Therefore, Comparison function should return false for equal values when equivalence is expected.
4. Use map::operator  to modify/retrieve existing elements in the map
Use map::insert to add new elements
5. Iterator can be implicitely converted to reverse_iterator.
reverse_iterator to iterator: use member base() function.
const_cast works for conversion from const_iterator to iterator of strings and vector because they are char* and T* pointers. For others to convert from const_iterator to iterator use std::advance (i, distance
7. v.reserve(size) does not invoke constructor (even default). It simply allocates more memory, if any, to hold size objects. Insertion of value at v.end () is wrong in general, use back_inserter (v) instead. Insertion is important and not assignment even after reserve.
8. v.remove () may not erase elements from the container, therefore, v.size() may not change after v.remove.
9. binary_search should receive same comparison function as the sort function did.
10. Custom function objects should be adaptable. To make them adaptable inherit from unary_function or binary_function. Adaptable function objects can be used with not1.
ptr_fun, mem_fun and mem_fun_ref are used to adapt member functions for algorithms like for_each.