foo.cc:15:7: warning: integer constant is too large for its type
   15 | int f[9999999999999999999999999999999999999999999999];
      |       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:15:5: error: size of array ‘f’ exceeds maximum object size ‘9223372036854775807’
   15 | int f[9999999999999999999999999999999999999999999999];
      |     ^
foo.cc: In function ‘int main()’:
foo.cc:21:9: error: ‘f’ was not declared in this scope
   21 |         f[1]=f[2]=1;
      |         ^