/in/foo.c: In function 'main':
/in/foo.c:19:14: warning: implicit declaration of function 'prime'; did you mean 'prinme'? [-Wimplicit-function-declaration]
   19 |         flag=prime(num);
      |              ^~~~~
      |              prinme
/in/foo.c: In function 'prinme':
/in/foo.c:14:1: warning: control reaches end of non-void function [-Wreturn-type]
   14 | }
      | ^
/usr/bin/ld: /tmp/cctl838J.o: in function `main':
foo.c:(.text.startup+0x1e): undefined reference to `prime'
collect2: error: ld returned 1 exit status