View Compilation Error

0_0_38863513_31176.cpp:2:1: error: '_int64' does not name a type
    2 | _int64 num(int n)
      | ^~~~~~
0_0_38863513_31176.cpp: In function 'int main()':
0_0_38863513_31176.cpp:16:9: error: '_int64' was not declared in this scope
   16 |         _int64 a;
      |         ^~~~~~
0_0_38863513_31176.cpp:20:17: error: 'a' was not declared in this scope
   20 |                 a = num(n);
      |                 ^
0_0_38863513_31176.cpp:20:21: error: 'num' was not declared in this scope; did you mean 'enum'?
   20 |                 a = num(n);
      |                     ^~~
      |                     enum