Return Type Funtion without passing any Argument.

#include<stdio.h>
#include<conio.h>
int sum();

main()
{
int x;
x=sum();
printf("Sum= %d",x);
getch();
}
int sum(int x,int y)
{
int a , b;
printf("Enter two numbers");
scanf("%d %d",&a,&b);
int sum;
sum=x+y;
return sum;
}