/in/foo.c: In function 'Search':
/in/foo.c:22:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^
/in/foo.c:18:3: warning: 'flag' may be used uninitialized in this function [-Wmaybe-uninitialized]
 if(flag==0)
   ^
/in/foo.c: In function 'main':
/in/foo.c:18:3: warning: 'flag' may be used uninitialized in this function [-Wmaybe-uninitialized]
 if(flag==0)
   ^
/in/foo.c:4:15: note: 'flag' was declared here
  int index=-1,flag,i;
               ^~~~