Functions

Reference Parameters (Syntax 5.5 : Constant Reference Parameters)

Syntax 5.5 : Constant Reference Parameters

const type_name& parameter_name

Example:	const Employee& e
Purpose:	Define a parameter that is bound to a variable in the function call, to avoid the cost of copying the variable into the parameter variable.

Reference parameters are more efficient than value parameters because they do not make copies of the parameters.
Passing variables by constant reference improves performance, but prevents the function from changing the value of the parameter.
Objects make good constant reference parameters because they tend to have several attributes that need to be copied. Passing numbers by constant reference is generally not worth the effort.