View Compilation Error

0_0_35193643_18246.cpp: In function 'int main()':
0_0_35193643_18246.cpp:12:9: error: 'ture' was not declared in this scope
   while(ture)
         ^
0_0_35193643_18246.cpp:17:14: error: cannot convert 'std::stack<_Tp, _Sequence>::empty<int, std::deque<int, std::allocator<int> > >' from type 'bool (std::stack<int>::)() const' to type 'bool'
     while(!a.empty)
              ^
0_0_35193643_18246.cpp:17:14: error: in argument to unary !
0_0_35193643_18246.cpp:19:12: error: 's' was not declared in this scope
      cout<<s.top;
            ^
0_0_35193643_18246.cpp:28:9: error: 's' was not declared in this scope
    else s.push(ch);
         ^