I just want to know, how to use the function "sum" effectively, returned in the following code.

distance is a structure.

Code:`distance &sum(distance L1, distanceL2);`

distance L3; // global structure

distance &sum(distance L1,distance L2)

{

L3.feet=L1.feet+L2.feet+(L1.inches+L2.inches)/12;

L3.inches=(L1.inches+L2.inches)%12;

return L3;

}