View Compilation Error

0_0_19371763_20777.cpp: In function 'int main()':
0_0_19371763_20777.cpp:7:11: error: 'cin' was not declared in this scope
     while(cin>>n>>r)
           ^
0_0_19371763_20777.cpp:12:13: error: 'cout' was not declared in this scope
             cout<<"-";
             ^
0_0_19371763_20777.cpp:21:13: error: 'cout' was not declared in this scope
             cout<<a[i];
             ^
0_0_19371763_20777.cpp:22:9: error: 'cout' was not declared in this scope
         cout<<endl;
         ^
0_0_19371763_20777.cpp:22:15: error: 'endl' was not declared in this scope
         cout<<endl;
               ^