SATYAM PLACEMENT QUESTION on c and c++

(1)Which of following operator can't be overloaded.
a)==b) ++ c) ?! d) <= 2. For the following C program
#includevoid main(){printf("Hello World");}
3. For the following C program:
swap(int x,y){int temp;temp=x;x=y;y=temp;}
main(){intx=2;y=3;swap(x,y);}
After calling swap, what are the values x & y?
4. For the following C program
struct base {int a,b;base();int virtual function1();}
struct derv1: