View Compilation Error

0_0_32594363_17918.cpp: In function 'int main()':
0_0_32594363_17918.cpp:6:3: error: 'cin' was not declared in this scope
   cin>>T;
   ^
0_0_32594363_17918.cpp:10:33: error: 'sqrt' was not declared in this scope
     for(a=(int)(sqrt((double)n+1)-1);a>0;a--){
                                 ^
0_0_32594363_17918.cpp:16:25: error: 'cout' was not declared in this scope
                         cout<<(n/a-a)/2<<endl;
                         ^
0_0_32594363_17918.cpp:16:42: error: 'endl' was not declared in this scope
                         cout<<(n/a-a)/2<<endl;
                                          ^
0_0_32594363_17918.cpp:22:7: error: 'cout' was not declared in this scope
       cout<<-1<<endl;
       ^
0_0_32594363_17918.cpp:22:17: error: 'endl' was not declared in this scope
       cout<<-1<<endl;
                 ^