/in/foo.cc: In function 'int main()':
/in/foo.cc:8:20: error: 'o' was not declared in this scope
  double n = 0, m = o, c = o, d  = o;
                    ^
/in/foo.cc:11:2: error: 'c' was not declared in this scope
  c = * 0.8;
  ^
/in/foo.cc:11:8: error: invalid type argument of unary '*' (have 'double')
  c = * 0.8;
        ^~~
/in/foo.cc:12:2: error: 'd' was not declared in this scope
  d = n - c;
  ^