/in/foo.c: In function 'main':
/in/foo.c:6:2: warning: implicit declaration of function 'input' [-Wimplicit-function-declaration]
  input(n, a);
  ^~~~~
/in/foo.c:8:15: warning: implicit declaration of function 'search' [-Wimplicit-function-declaration]
  printf("%d", search(target, a, n));
               ^~~~~~
/in/foo.c: In function 'input':
/in/foo.c:20:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^