View Compilation Error

0_0_20134613_7247.cpp:2:16: error: expected identifier before ';' token
 using namespace;
                ^
0_0_20134613_7247.cpp: In function 'int main()':
0_0_20134613_7247.cpp:6:8: error: 'cin' was not declared in this scope
  while(cin>>a>>b){
        ^
0_0_20134613_7247.cpp:6:8: note: suggested alternative:
In file included from 0_0_20134613_7247.cpp:1:0:
GCC4.9.2/x86_64-w64-mingw32/include/c++/iostream:60:18: note:   'std::cin'
   extern istream cin;  /// Linked to standard input
                  ^
0_0_20134613_7247.cpp:7:3: error: 'cout' was not declared in this scope
   cout<<a+b;
   ^
0_0_20134613_7247.cpp:7:3: note: suggested alternative:
In file included from 0_0_20134613_7247.cpp:1:0:
GCC4.9.2/x86_64-w64-mingw32/include/c++/iostream:61:18: note:   'std::cout'
   extern ostream cout;  /// Linked to standard output
                  ^