foo.c: In function 'main':
foo.c:8:2: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
  for(i=2;i<=b-1&&a;i++)
  ^~~
foo.c:11:3: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
   if(a)
   ^~
foo.c:6:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&b);
  ^~~~~~~~~~~~~~

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