A program to demonstrate the concept of functions returning values

#include<iostream.h> 
 #include<conio.h> 
 int average (int, int, int) ; 
 int main () 
 { 
              int a,b,c,r; 
              clrscr(); 
              cout<<"Enter three numbers :"; 
              cin>>a>>b>>c; 
               r=average(a,b,c); 
              cout<<"The average of three numbers is: "<<r; 
              getch(); 
           return 0; 
 } 
               int average(int x,int y,int z) 
              { 
                    int avg; 
                            avg = (x+y+z)/3; 
                    return avg; 
              }