/in/foo.c: In function 'search':
/in/foo.c:22:12: warning: 'flag' may be used uninitialized in this function [-Wmaybe-uninitialized]
     return flag;
            ^~~~
/in/foo.c: In function 'main':
/in/foo.c:41:9: warning: 'flag' may be used uninitialized in this function [-Wmaybe-uninitialized]
         printf("%d", index);
         ^~~~~~~~~~~~~~~~~~~