foo.c: In function 'main':
foo.c:13:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&w,&n);
  ^~~~~~~~~~~~~~~~~~~
foo.c:14:19: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  for(i=0;i<n;i++) scanf("%d",&p[i]);
                   ^~~~~~~~~~~~~~~~~