1) In the expression

 int x1 = 10 ; 
 
Which is the lvalue and which is the rvalue . 

2)
int y1 = x1 + 1 ; 

Is y1 a lvalue or rvalue. 


3)
 int* ptr1 = &x1 ; 
 
 Is ptr1 a lvalue or rvalue ; 
 Is x1 a lvalue or rvalue ; 
 
4) 
  int x1 = 5 ; 
  int y1 = 6 ; 
  
  Is the expression ( x1 + y1 ) a lvalue or rvalue ?
  
5)   
 int x1 = 5 ; int b1 = 6 ; 
 int* ptr = &(a1 + b1);. 
 
 Is this a valid statement and why not ?