/in/foo.cc: In function 'int main()':
/in/foo.cc:12:25: error: invalid type argument of unary '*' (have 'double')
  s=((p-a)*(p-b)*(p-c))**0.5;
                         ^~~
/in/foo.cc:13:17: warning: spurious trailing '%' in format [-Wformat=]
  printf("s=d%",s);
                 ^
/in/foo.cc:13:17: warning: too many arguments for format [-Wformat-extra-args]