Please help me to understand this C++ Code through correct Output

Question

void main( )
{
int Ar[ ] = { 6 , 3 , 8 , 10 , 4 , 6 , 7} ;
int *Ptr = Ar , I ;
cout<<++*Ptr++ << '@' ;
I = Ar[3] - Ar[2] ;
cout<<++*(Ptr+I)<<'@'<<"\n" ;
cout<<++I + *Ptr++ << '@' ;
cout<<*Ptr++ <<'@'<< '\n' ;
for( ; I >=0 ; I -=2)
cout<<Ar[I] << '@' ;
}