foo.c: In function 'prime':
foo.c:27:1: warning: control reaches end of non-void function [-Wreturn-type]
   27 | }
      | ^
foo.c: In function 'main':
foo.c:44:5: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   44 |     scanf("%d %d",&i,&j);
      |     ^~~~~~~~~~~~~~~~~~~~
foo.c:47:9: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   47 |         scanf("%d",&a[n]);
      |         ^~~~~~~~~~~~~~~~~
foo.c:51:9: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   51 |         scanf("%d",&b[n]);
      |         ^~~~~~~~~~~~~~~~~

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