/in/foo.c: In function 'main':
/in/foo.c:19:19: warning: implicit declaration of function 'sqrt' [-Wimplicit-function-declaration]
   19 |                 y=sqrt(5*x+10);
      |                   ^~~~
/in/foo.c:2:1: note: include '<math.h>' or provide a declaration of 'sqrt'
    1 | #include <stdio.h>
  +++ |+#include <math.h>
    2 | #include <stdio.h>
/in/foo.c:19:19: warning: incompatible implicit declaration of built-in function 'sqrt' [-Wbuiltin-declaration-mismatch]
   19 |                 y=sqrt(5*x+10);
      |                   ^~~~
/in/foo.c:19:19: note: include '<math.h>' or provide a declaration of 'sqrt'