Implement Stack using Queues

1 classStack {2  Public:3     //Push element x onto stack.4     voidPushintx) {5         if(Q1.empty () &&q2.empty ())6 Q1.push (x);7         Else 8         {9             if(Q1.empty ())Ten Q2.push (x); One             ElseQ1.push (x); A         } -          -     } the  -     //removes the element on top of the stack. -     voidpop () { -          if(Q1.empty () &&q2.empty ()) +          return ; -          Else  +          { A              if(Q1.empty ()) at              { -                  if(q2.size () = =1) - Q2.pop (); -                  Else -                  { -                       while(Q2.size () >1) in                      { - Q1.push (Q2.front ()); to Q2.pop (); +                      } - Q2.pop (); the                  } *              } $              ElsePanax Notoginseng              { -                   if(q1.size () = =1) the Q1.pop (); +                  Else A                  { the                       while(Q1.size () >1) +                      { - Q2.push (Q1.front ()); $ Q1.pop (); $                      } - Q1.pop (); -                  } the              } -              }Wuyi          } the      -  Wu     //Get the top element. -     intTop () { About          if(Q1.empty () &&q2.empty ()) $          return-1; -          Else  -          { -              if(Q1.empty ()) A              { +                  returnQ2.back (); the              } -              Else $              { the                  returnQ1.back (); the              } the              } the          } -      in  the     //Return Whether the stack is empty. the     BOOLempty () { About         if(Q1.empty () &&q2.empty ()) the         return true; the         Else return false; the     } + Private: -queue<int>Q1; thequeue<int>Q2;Bayi};

Implement Stack using Queues