View Compilation Error

0_0_32146301_14545.cpp: In function 'int main()':
0_0_32146301_14545.cpp:10:11: error: 'cin' was not declared in this scope
     while(cin>>n){
           ^
0_0_32146301_14545.cpp:11:9: error: 'cout' was not declared in this scope
         cout<<a[n]<<endl;
         ^
0_0_32146301_14545.cpp:11:21: error: 'endl' was not declared in this scope
         cout<<a[n]<<endl;
                     ^