Constant and Default Parameters

• Review of Parameter Passing Schemes
  • Call by Value (Copy Semantics)
  • Call by Reference (Aliasing Semantics)
  • Example:  add.cpp
• Constant Parameters
  • Useful in those situations where you want the efficiency of call-by-reference, but the safety of call-by-value
  • To implement use the keyword:  const before the parameter type.
  • e.g.:  const int &x
• Default Parameters
  • Useful for when some of the parameters take typical values and only sometimes take other values
  • Example:
    • To increment a variable x by 1, we can write:  x = x + 1; or x += 1;
    • As a special case of the common operation, C++ provides x++;or ++x;
    • Likewise we can write add.cpp to increment by one, if no second parameter is supplied
• Function Overloading
  • Functions can be overloaded (given the same name), as long as the compiler can distinguish the function based on the type and number of parameters (e.g., see promptAndGet in add.cpp)