foo.c: In function 'px':
foo.c:18:1: warning: control reaches end of non-void function [-Wreturn-type]
   18 | }
      | ^
foo.c: In function 'main':
foo.c:22:9: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   22 |  int x1;scanf("%d",&x1);
      |         ^~~~~~~~~~~~~~~
foo.c:23:9: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   23 |  int x2;scanf("%d",&x2);
      |         ^~~~~~~~~~~~~~~
foo.c:24:9: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   24 |  int x3;scanf("%d",&x3);
      |         ^~~~~~~~~~~~~~~

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