/in/foo.c: In function 'main':
/in/foo.c:17:24: warning: implicit declaration of function 'sqrt' [-Wimplicit-function-declaration]
   17 |                 x1=(-b+sqrt(delta))/(2*a);
      |                        ^~~~
/in/foo.c:2:1: note: include '<math.h>' or provide a declaration of 'sqrt'
    1 | #include <stdio.h>
  +++ |+#include <math.h>
    2 | int main()
/in/foo.c:17:24: warning: incompatible implicit declaration of built-in function 'sqrt' [-Wbuiltin-declaration-mismatch]
   17 |                 x1=(-b+sqrt(delta))/(2*a);
      |                        ^~~~
/in/foo.c:17:24: note: include '<math.h>' or provide a declaration of 'sqrt'
/in/foo.c:22:26: warning: incompatible implicit declaration of built-in function 'sqrt' [-Wbuiltin-declaration-mismatch]
   22 |                 imagpart=sqrt(delta)/(2*a);
      |                          ^~~~
/in/foo.c:22:26: note: include '<math.h>' or provide a declaration of 'sqrt'
/in/foo.c:17:24: warning: 'delta' may be used uninitialized [-Wmaybe-uninitialized]
   17 |                 x1=(-b+sqrt(delta))/(2*a);
      |                        ^~~~~~~~~~~
/in/foo.c:4:21: note: 'delta' was declared here
    4 |         float a,b,c,delta,x,x1,x2,realpart,imagpart;
      |                     ^~~~~