C++ FAQ Celebrating Twenty-One Years of the C++ FAQ!!!
(Click here for a personal note from Marshall Cline.)
Section 13:
13.1 What's the deal with operator overloading?
13.2 What are the benefits of operator overloading?
13.3 What are some examples of operator overloading?
13.4 Is operator overloading supposed to make the class' code clearer?
13.5 What operators can/cannot be overloaded?
13.6 Overloading operator== to use string comparison?
13.7 Can I create operator** for to-the-power-of?
13.8 But which operators should I override?
13.9 Guidelines / "rules of thumb" for overloading operators?
13.10 Creating a subscript operator for a Matrix class?
13.11 Should my Matrix interface look like an array-of-array?
13.12 Part two of making my Matrix interface look like an array-of-array?
13.13 Designing classes from the outside-in vs. inside-out?
13.14 Overloading prefix/postfix forms of operators ++ and --?
13.15 Which is more efficient: i++ or ++i?
[13.4] But operator overloading makes my class look ugly; isn't it supposed to make my code clearer?

Operator overloading makes life easier for the users of a class, not for the developer of the class!

Consider the following example. 

class Array {
public:
  int& operator[] (unsigned i);      // Some people don't like this syntax
  ...
};

inline
int& Array::operator[] (unsigned i)  // Some people don't like this syntax
{
  ...
}
Some people don't like the keyword operator or the somewhat funny syntax that goes with it in the body of the class itself. But the operator overloading syntax isn't supposed to make life easier for the developer of a class. It's supposed to make life easier for the users of the class: 
int main()
{
  Array a;
  a[3] = 4;   // User code should be obvious and easy to understand...
  ...
}
Remember: in a reuse-oriented world, there will usually be many people who use your class, but there is only one person who builds it (yourself); therefore you should do things that favor the many rather than the few.