View Compilation Error

0_0_27574916_402.cpp: In function 'int main()':
0_0_27574916_402.cpp:6:2: error: 'cin' was not declared in this scope
  cin>>a1>>a2;
  ^
0_0_27574916_402.cpp:30:2: error: 'cout' was not declared in this scope
  cout<<endl;
  ^
0_0_27574916_402.cpp:30:8: error: 'endl' was not declared in this scope
  cout<<endl;
        ^