View Compilation Error

0_0_30278399_7348.cpp: In function 'int main()':
0_0_30278399_7348.cpp:30:12: error: 'cin' was not declared in this scope
     while (cin>>n>>k&& n)
            ^
0_0_30278399_7348.cpp:46:14: error: 'cout' was not declared in this scope
              cout<<t;
              ^
0_0_30278399_7348.cpp:48:14: error: 'cout' was not declared in this scope
              cout<<" "<<t;
              ^
0_0_30278399_7348.cpp:51:9: error: 'cout' was not declared in this scope
         cout<<"-1";
         ^
0_0_30278399_7348.cpp:52:9: error: 'cout' was not declared in this scope
         cout<<endl;}
         ^
0_0_30278399_7348.cpp:52:15: error: 'endl' was not declared in this scope
         cout<<endl;}
               ^