I have a problem using the Logical OR operator in C++. The problem is coming that the right-side expression is not evaluated if the left-side is true. I have two deque-s and I need to popLeft from them with a while, but if I can pop from the first deque, I don't pop from the second because is not evaluated, by the OR operator. How can I overcome this problem. Here is the piece of code: while( D.popLeft( k ) || E.popLeft( m ) ) { if( k < m ) { C.pushRight( k ); E.pushLeft( m ); } else { C.pushRight( m ); D.pushLeft( k ); } }