Prefferred method of inserting in map

[sunnypalsingh]

Suppose I have map

map<string, int> Employees;

Which of the following method are best to use for insertion?

1. Assignment using array index notation

Employees["Mike C."] = 5234;
 Employees["Charlie M."] = 3374;

2. Assignment using member function insert() and STL pair

Employees.insert(std::pair<string,int>("David D.",1923));

3. Assignment using member function insert() and "value_type()"

Employees.insert(map<string,int>::value_type("John A.",7582));

4. Assignment using member function insert() and "make_pair()"

Employees.insert(std::make_pair("Peter Q.",5328));