Overloading

Objectives

1. Discuss function and operator overloading.
2. Implement an overloaded constructor.

Notes

• Reference: Page 38 of your book.
• C++ allows us to have functions and operators with the same name.
  • This can lead to complexities but it is a powerful thing.
  • We will begin to explore this for convenience right now.
  • We will be back to look it other things later.
• In c++ two functions can have the same name as long as the function signature is different
• A function signature is
  • The function name
  • Parameters, including type, variability and constantness.
  • The number of parameters.
• The signature does not include
  • The return type
  • some modifiers
• Look at the Hello functions in hello.cpp.
• The compiler needs is able to deduce the function to call from the parameter list.
  • But when types are coercable to multiple parameters, there is ambiguity.
  • Look at the Bad functions in hello.cpp
    • In this case, the compiler can't decide which function to cast the double to.
• We can also overload operators.
  • type operator symbol(parameters);
  • For example: string operator +(string a, int b);
    • Defines + for a string and an int.
    • Returns a string
    • Computes a+b where
      • a is a string
      • b is an integer.
• We can overload most c++ operators.
  • We will explore this in more detail later.