View Compilation Error

0_0_28209429_8716.cpp: In function 'int main()':
0_0_28209429_8716.cpp:13:17: error: 'cin' was not declared in this scope
         int t,i;cin>>t;while(t--) 
                 ^
0_0_28209429_8716.cpp:27:3: error: 'cout' was not declared in this scope
   cout<<l<<endl;
   ^
0_0_28209429_8716.cpp:27:12: error: 'endl' was not declared in this scope
   cout<<l<<endl;
            ^