foo.c: In function 'main':
foo.c:6:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &n);
  ^~~~~~~~~~~~~~~
foo.c:9:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", & a[i]);
   ^~~~~~~~~~~~~~~~~~~
foo.c:19:7: warning: 't' may be used uninitialized in this function [-Wmaybe-uninitialized]
  while(t!=0)
       ^
foo.c:13:4: warning: 'x' may be used uninitialized in this function [-Wmaybe-uninitialized]
  if(x<y)
    ^
foo.c:13:4: warning: 'y' may be used uninitialized in this function [-Wmaybe-uninitialized]

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