/in/foo.c: In function 'qiujie':
/in/foo.c:8:28: warning: format '%f' expects argument of type 'double', but argument 2 has type 'int' [-Wformat=]
    8 |                 printf("%.2f\n",x);
      |                         ~~~^    ~
      |                            |    |
      |                            |    int
      |                            double
      |                         %.2d
/in/foo.c:14:36: warning: format '%f' expects argument of type 'double', but argument 2 has type 'int' [-Wformat=]
   14 |                         printf("%.2f\n",x);
      |                                 ~~~^    ~
      |                                    |    |
      |                                    |    int
      |                                    double
      |                                 %.2d
/in/foo.c:19:36: warning: format '%f' expects argument of type 'double', but argument 2 has type 'int' [-Wformat=]
   19 |                         printf("%.2f\n%.2f\n",x1,x2);
      |                                 ~~~^          ~~
      |                                    |          |
      |                                    double     int
      |                                 %.2d
/in/foo.c:19:42: warning: format '%f' expects argument of type 'double', but argument 3 has type 'int' [-Wformat=]
   19 |                         printf("%.2f\n%.2f\n",x1,x2);
      |                                       ~~~^       ~~
      |                                          |       |
      |                                          double  int
      |                                       %.2d
/in/foo.c:22:25: error: 'realpart' undeclared (first use in this function)
   22 |                         realpart=-b/(2*a);
      |                         ^~~~~~~~
/in/foo.c:22:25: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:23:25: error: 'imagpart' undeclared (first use in this function)
   23 |                         imagpart=sqrt(-delta)/(2*a);
      |                         ^~~~~~~~