foo.c:1:19: warning: extra tokens at end of #include directive
 #include <stdio.h>#include <stdio.h>
                   ^
foo.c: In function 'main':
foo.c:4:10: warning: unused variable 'j' [-Wunused-variable]
 {int x,i,j;
          ^
foo.c:5:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&x);
  ^~~~~~~~~~~~~~

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