foo.c: In function 'main':
foo.c:9:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d%d",&n1,&n2,&n3);
  ^~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.c:11:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",&a1[i]);
   ^~~~~~~~~~~~~~~~~~
foo.c:13:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",&a2[i]);
   ^~~~~~~~~~~~~~~~~~
foo.c:15:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",&a3[i]);
   ^~~~~~~~~~~~~~~~~~
#'target_mem_ref' not supported by expression#'foo.c:19:3: warning:  may be used uninitialized in this function [-Wmaybe-uninitialized]
   printf("%d ",c1[i]);
   ^~~~~~~~~~~~~~~~~~~
#'target_mem_ref' not supported by expression#'foo.c:21:3: warning:  may be used uninitialized in this function [-Wmaybe-uninitialized]
   printf("%d ",c2[i]);
   ^~~~~~~~~~~~~~~~~~~
foo.c: In function 'Merge':
foo.c:48:10: warning: 'c[20000]' may be used uninitialized in this function [-Wmaybe-uninitialized]
  return c[20000];
         ~^~~~~~~

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