foo.c:2:6: warning: return type of 'main' is not 'int' [-Wmain]
 void main()
      ^~~~
foo.c: In function 'main':
foo.c:16:9: warning: 'return' with a value, in function returning void
  return 0;
         ^
foo.c:2:6: note: declared here
 void main()
      ^~~~
foo.c:6:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&i);
  ^~~~~~~~~~~~~~

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