View Compilation Error

0_0_39645828_17373.cpp:2:2: error: invalid preprocessing directive #using
    2 | #using namespace std;
      |  ^~~~~
0_0_39645828_17373.cpp: In function 'int main()':
0_0_39645828_17373.cpp:6:5: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    6 |     cin>>a>>b;
      |     ^~~
      |     std::cin
In file included from 0_0_39645828_17373.cpp:1:
gcc-13.1.0/lib/gcc/x86_64-w64-mingw32/13.1.0/include/c++/iostream:62:18: note: 'std::cin' declared here
   62 |   extern istream cin;           ///< Linked to standard input
      |                  ^~~
0_0_39645828_17373.cpp:7:15: error: expected ';' before '}' token
    7 |     return a+b
      |               ^
      |               ;
......
   10 | }
      | ~