Program Of Call By Refrence in c

#include<stdio.h>

#include<conio.h>

int sum(int &a,int &b);

main()

{

int x,y,z;

clrscr();

printf("ENter First NUmber=");

scanf("%d",&x);

printf("ENter Second NUmber=");

scanf("%d",&y);

z=sum(x,y);

printf("\n Answer=%d",z);

getch();

}

int sum(int &a,int &b)

{

int c;

c= a + b;

return c;

}