/in/foo.cc: In function 'int main()':
/in/foo.cc:10:33: error: expected primary-expression before 'double'
   10 |                 int b=(int)sqrt(double a);
      |                                 ^~~~~~
/in/foo.cc:5:17: warning: unused variable 'b' [-Wunused-variable]
    5 |         int n,a,b;
      |                 ^