View Compilation Error

0_0_33282397_25393.cpp:2:7: error: expected nested-name-specifier before 'spacename'
 using spacename std;
       ^
0_0_33282397_25393.cpp: In function 'int main()':
0_0_33282397_25393.cpp:5:5: error: 'cin' was not declared in this scope
     cin>>a>>b;
     ^
0_0_33282397_25393.cpp:5:5: note: suggested alternative:
In file included from 0_0_33282397_25393.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_33282397_25393.cpp:6:5: error: 'cout' was not declared in this scope
     cout<<a+b;
     ^
0_0_33282397_25393.cpp:6:5: note: suggested alternative:
In file included from 0_0_33282397_25393.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
                  ^