/in/foo.cc: In function 'void qsort(int, int)':
/in/foo.cc:9:4: warning: 'a[<unknown>]' is used uninitialized in this function [-Wuninitialized]
 mid=a[(l+r)/2];
 ~~~^~~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:30:12: warning: 'i' is used uninitialized in this function [-Wuninitialized]
  for(int i=i;i<=n;i++)
            ^