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",&k);
  ^~~~~~~~~~~~~~
foo.c:7:7: warning: 'ch' is used uninitialized in this function [-Wuninitialized]
  while(ch!='\n')
       ^

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