1. Reference Parameters

2. References Reference variable Alias / shortcut to another variable
Declared with Type& Name

3. References
References do not have their own value

4. References Refer to Variables
A reference MUST refer to another variable

5. Reference Parameters Reference parameter indicates pass by reference:
Standard is pass by value:

6. Reference Parameter
x is a link back to num

7. Reference Parameter Uses
Another way to get information back from a function:

8. Reference Parameter Uses
Used in some library functions cin.get(char &c) get one char, possibly whitespace

9. Reference Parameter Uses
Way to get multiple pieces of information back from function:

10. Reference Parameter Efficiency
Value parameters require copying parameter
What if parameter is huge?
Reference parameter does not copy… links
Minimal overhead
Danger of modification!

11. Const References A const & can not be modified:
Any attempt is compile error:

12. Function IO Ways to give functions info
Global variables I set this random variable for you to read…
Parameters Here is the list of things you asked for

13. Function IO Ways to give functions info
Global variables I set this random variable for you to read…
Parameters Here is the list of things you asked for

14. Returning Information
Can get information from function with:
Global variables I think you set this random variable…
Reference Parameters I passed you these things by reference, you may have changed them for me…
Return value You always give me back an int…

15. Returning Information
Can get information from function with:
Global variables I think you set this random variable…
Reference Parameters I passed you these things by reference, you may have changed them for me…
Return value You always give me back an int…

16. When To Reference Function produces 1 output
return it
Function needs to produce 2+ outputs
extra reference parameters for outputs
return void

17. When To Reference Function must modify inputs
Are you sure??? If so use refs:
Function needs to work with large data item:
const refs