function doesn't display the return value?

function doesn't display the return value?

Why it doesn't return any value? The output should be 155 but it always
display 0. why?
int main()
{
int i=5;
printf("%d",fun(fun(fun(fun( fun(i))))));
return 0;
}
void fun(int i)
{
if(i%2) return (i+(7*4)-(5/2)+(2*2));
else return (i+(17/5)-(34/15)+(5/2));
}
But if I change
void fun(int i) // It doesn't work, case 1
to
int fun(int i) //It works fine, case 2
If fun doesn't return any value in case 1 ( void fun(int i) ), then how come
fun(fun(fun(fun( fun(i)))))); this statement is working?