foo.c: In function 'main':
foo.c:7:2: error: expected ';' before 'printf'
  printf("请输入一个正整数：\n");
  ^~~~~~
foo.c:11:3: error: 'k' undeclared (first use in this function)
   k=num%i;
   ^
foo.c:11:3: note: each undeclared identifier is reported only once for each function it appears in
foo.c:8:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&num);
  ^~~~~~~~~~~~~~~~

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