void foo(int const* x, int* const y) 
{ 
    int a; 
    
    *x = 5; //1 
    x = &a; //2 
    *y = 5; //3 
    y = &a; //4 
     
} 
int main() 
{ 
    int x,y; 
    foo(&x,&y); 
}